A functionalized propylene-based elastomer and its application

Abstract

The invention discloses a functionalized propylene-based elastomer and an application thereof. The functionalized propylene-based elastomer comprises the following raw materials in parts by weight: 64.5-80 parts of a propylene-based elastomer resin, 0.2-2.13 parts of a maleic anhydride monomer, 0.3-1.83 parts of a grafting monomer, 0.01-1.5 parts of an initiator, and 0.05-1.5 parts of a crosslinking inhibitor. The grafting monomer contains a carbon-carbon double bond, a carboxyl substituent, an alicyclic structure, and a carbon chain structure of C8 to C12. The invention enhances the impact strength of the propylene-based elastomer and solves the adhesion problem of the propylene-based elastomer by adding a grafting monomer with a specific structure to the functionalized propylene-based elastomer. The functionalized propylene-based elastomer is applied to a modified PP film to improve the impact resistance and low-temperature resistance of the PP film and reduce the haze of the PP film.

Description

Technical Field

[0001] The present invention belongs to the field of functional polymer materials, and in particular relates to a functionalized propylene-based elastomer and applications thereof. Background Art

[0002] Polypropylene (PP) film is transparent, making it easy to see its contents, and has excellent mechanical properties, making it widely used in the packaging industry. PP film is typically made from homopolymer polypropylene. For packaging applications, PP film requires high impact resistance, but homopolymer polypropylene films have low impact strength. Furthermore, for visualizing and aesthetically pleasing contents, the film also requires good optical properties. Furthermore, polypropylene has poor low-temperature resistance, and conventional PP film is not resistant to low temperatures, limiting its use in northern China during winter.

[0003] In the prior art, to improve the impact resistance and low-temperature resistance of PP films, polyolefin elastomers are typically used to modify the films. For example, propylene-based elastomers are used to modify PP films. However, the addition of large amounts of elastomer is costly, and the addition of large amounts of elastomer often results in a high haze in the PP film, which reduces optical properties such as transparency. Furthermore, unmodified polyolefin elastomers often suffer from blocking, making it extremely difficult to process them into pellets (processing and granulation) during the production process. Therefore, developing an anti-blocking functionalized propylene-based elastomer and applying it to modified PP films to achieve excellent impact resistance, low-temperature resistance, and haze is an urgent issue to be addressed. Summary of the Invention

[0004] In response to the deficiencies in the prior art, the present invention discloses a functionalized propylene-based elastomer. By adding a grafting monomer with a specific structure to the functionalized propylene-based elastomer, the present invention enhances the impact strength of the propylene-based elastomer and solves the adhesion problem of the propylene-based elastomer. The functionalized propylene-based elastomer is applied to a modified PP film to improve the impact resistance and low-temperature resistance of the PP film and reduce the haze of the PP film. Compared with an unmodified propylene-based elastomer, the functionalized propylene-based elastomer of the present invention can enable the PP film to have high impact strength and low-temperature resistance at a low addition amount, while maintaining low haze and high transparency.

[0005] The present invention aims to provide a functionalized propylene-based elastomer, which comprises the following raw materials in parts by weight: 64.5-80 parts of propylene-based elastomer resin, 0.2-2.13 parts of maleic anhydride monomer, 0.3-1.83 parts of grafting monomer, 0.01-1.5 parts of initiator, and 0.05-1.5 parts of crosslinking inhibitor, wherein the grafting monomer contains a carbon-carbon double bond, a carboxyl substituent, an alicyclic structure, and a carbon chain structure of C8 to C12.

[0006] The present invention adds a grafting monomer containing a carbon-carbon double bond, a carboxyl substituent, an alicyclic structure and a carbon chain structure of C8 to C12 into the preparation of a functionalized propylene-based elastomer. The grafting monomer is grafted onto the propylene-based elastomer resin to form a chain segment. The alicyclic structure contained in the chain segment enhances the hardness and impact strength of the propylene-based elastomer. The carboxyl group contained in the chain segment forms a hydrogen bond with the oxygen on the ester group of the maleic anhydride chain segment, further improving the hardness and impact strength of the propylene-based elastomer. Moreover, the alicyclic structure is not easily oxidized to quinone and yellowed like a benzene ring, thereby improving the yellowing resistance of the propylene-based elastomer.

[0007] Preferably, the functionalized propylene-based elastomer comprises the following raw materials in parts by weight: 71.5 parts of propylene-based elastomer resin, 1.85 parts of maleic anhydride monomer, 1.03 parts of grafting monomer, 0.9 parts of initiator, and 0.8 parts of cross-linking inhibitor, wherein the grafting monomer contains a carbon-carbon double bond, a carboxyl substituent, an alicyclic structure, and a C8-C12 carbon chain structure.

[0008] Preferably, the structural formula of the grafting monomer is as shown in formula (I):

[0009]

[0010] Wherein, R is a C8-C12 alkane substituent.

[0011] Preferably, the structural formula of the grafting monomer is as shown in formula (II):

[0012]

[0013] Preferably, the functionalized propylene-based elastomer further comprises 2-10 parts of a release agent, wherein the release agent is selected from silicone, hydrogen fluorine silicone oil, and ethylene bisstearamide in a weight ratio of 1:2-3:5-6.

[0014] There is the adhesion problem usually in propylene-based elastomer, because the propylene-based polymer crystallization process is much slower than the vinyl polymer under the same density, and just propylene-based polymer needs the longer time to realize complete crystallization.Therefore, when preparing propylene-based elastomer, propylene-based elastomer is not cooled off fully, just sticks together rapidly after being processed into pellet, and this makes that in preparation process, propylene-based elastomer is processed into pellet and becomes unusual difficulty.The present invention is by adding the antitackifier that contains silicone, hydrogen-containing fluorosilicone oil and ethylene bis stearamide in functionalized propylene-based elastomer, silicone is the polydimethylsiloxane of a series of different molecular weights, silicone runs through hydrogen-containing fluorosilicone oil and ethylene bis stearamide intermolecular, there is hydrogen bond interaction between the carboxyl and the ester group that contain in the fluoro group of hydrogen-containing fluorosilicone oil, the amide group of ethylene bis stearamide and the functionalized propylene-based elastomer, make the antitackifier that contains silicone, hydrogen-containing fluorosilicone oil, ethylene bis stearamide greatly improve the adhesion problem that propylene-based elastomer exists.

[0015] More preferably, the functionalized propylene-based elastomer further comprises 5.4 parts of a release agent, wherein the release agent is selected from silicone, hydrogen-containing fluorosilicone oil, and ethylene bisstearamide in a weight ratio of 1:2.5:5.5.

[0016] Preferably, the initiator includes at least one of 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane, 1,1-bis(tert-butylperoxide)3,3,5-trimethylcyclohexane, triphenylmethane-4,4',4"-triisocyanate, diisopropyl peroxide, dibenzoyl peroxide, bis(2-tert-butylperoxyisopropyl)benzene, tert-butylisopropyl peroxide, di-tert-butyl peroxide, tert-amyl peroxybenzoate, di-tert-amyl peroxide, tert-butyl peroxybenzoate, tert-butyl peroxy-2-ethylhexanoate, tert-butyl peroxy-3,5,5-trimethylhexanoate, di(2,4-dichlorobenzoyl)peroxide, and tert-butyl peroxy-2-ethylhexyl carbonate.

[0017] Preferably, the cross-linking inhibitor includes at least one of triphenyl phosphite, caprolactam, and stearamide.

[0018] Another object of the present invention is to provide a method for preparing the grafted monomer, comprising the following steps:

[0019] The compound of formula (III), a C8-C12 alkyl alcohol dissolved in a solvent, a strong acid catalyst, and a polymerization inhibitor are mixed, the temperature is raised to react, and the crude product is separated and purified to obtain a graft monomer;

[0020] The structural formula of the compound of formula (III) is shown below:

[0021]

[0022] Preferably, the molar ratio of the compound of formula (III) to the C8-C12 alkyl alcohol is 1:1.

[0023] Preferably, the strong acid catalyst includes at least one of p-toluenesulfonic acid, methanesulfonic acid, boron trifluoride etherate, scandium trifluoromethanesulfonate, and yttrium trifluoromethanesulfonate; the polymerization inhibitor includes at least one of hydroquinone, methyl hydroquinone, tert-butyl hydroquinone, 2,6-di-tert-butyl hydroquinone, N,N'-diphenyl-p-phenylenediamine, phenothiazine, and N-nitroso-cyclohexylhydroxylamine.

[0024] Another object of the present invention is to provide a method for preparing the functionalized propylene-based elastomer, characterized in that it comprises the following steps:

[0025] According to weight, propylene-based elastomer resin, maleic anhydride monomer, grafting monomer, initiator, crosslinking inhibitor and optional anti-sticking agent are added to a mixer and mixed evenly, and then added to an extruder through a main feed, and the initiator is added to the extruder through a side feed. The mixture is extruded to obtain a functionalized propylene-based elastomer.

[0026] Preferably, the extrusion temperature is 80°C to 220°C.

[0027] Preferably, the screw speed of the extruder is 200-400 r / min.

[0028] Preferably, the residence time of the extrusion is 30 to 60 seconds.

[0029] Another object of the present invention is to provide a use of the functionalized propylene-based elastomer in the preparation of polypropylene films or in functional polypropylene particles.

[0030] Preferably, the functional polypropylene particles are prepared from polypropylene, polyethylene and functionalized propylene-based elastomer in a mass ratio of 55:40:5.

[0031] The present invention uses a propylene elastomer containing a carboxyl substituent, an alicyclic structure, and a carbon chain structure of C8-C12 to modify a polypropylene film. The alicyclic structure within the propylene elastomer's molecular structure enhances the hardness and impact strength of the propylene elastomer. Furthermore, the carboxyl groups within the propylene elastomer's molecular structure form hydrogen bonds with the oxygen groups within the ester groups of the maleic anhydride segments, further enhancing the hardness and impact strength of the propylene elastomer. The carbon chain structure of C8-C12 within the propylene elastomer's molecular structure imparts a certain toughness to the propylene elastomer, improving the low-temperature resistance of the polypropylene film. Furthermore, the resulting polypropylene film maintains a low haze. DETAILED DESCRIPTION

[0032] In order to enable those skilled in the art to better understand the technical solutions of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts should fall within the scope of protection of the present invention.

[0033] The propylene-based elastomer was selected from 3980FL, ExxonMobil Chemical.

[0034] Silicone was selected from RF02070010, Shanghai Hanhong Technology Co., Ltd.

[0035] Polypropylene was selected from T30S, obtained from Maoming Branch of Sinopec.

[0036] The lubricant is selected from PEG lubricant produced by Clariant of Switzerland, with a molecular weight of 10,000.

[0037] Example 1: Preparation of grafted monomer.

[0038] The compound of formula (III) (20 mmol), 1-octanol (20 mmol) dissolved in 100 mL of tetrahydrofuran, p-toluenesulfonic acid (0.1 mmol), and hydroquinone (0.05 mmol) were added to a reaction flask, stirred, and heated to 65° C. for reaction for 8 hours. The crude product was placed in a 45° C. water bath for rotary evaporation and passed through a silica gel column in an eluent of ethyl acetate: petroleum ether (v / v) = 1:10 to obtain a grafted monomer A1 with a yield of 85.4%. The NMR data were characterized as follows: 1 H-NMR(CDCl3,400M-Hz), δ(ppm):10.65(s,1H,OH),5.00(d,2H,CH2),4.11(t,2H,CH2),2.49(m,1H,CH),2.21-2.12(m,3H,CH),1.93-1.48(m,11H,CHand CH2),1.30-1.26(s,8H,CH2),0.88(m,6H,CH2).

[0039] The structural formulas of the compound of formula (III) and the grafting monomer A1 are shown below:

[0040]

[0041] Example 2: Preparation of grafted monomer.

[0042] The compound of formula (III) (20 mmol), 1-decanol (20 mmol) dissolved in 100 mL of tetrahydrofuran, p-toluenesulfonic acid (0.1 mmol), and hydroquinone (0.05 mmol) were added to a reaction flask, stirred, heated to 65° C., and reacted for 8 hours. The crude product was placed in a 45° C. water bath for rotary evaporation and passed through a silica gel column in an eluent of ethyl acetate: petroleum ether (v / v) = 1:9 to obtain a grafted monomer A2 with a yield of 83.7%. The NMR data were characterized as follows: 1 H-NMR(CDCl3,400M-Hz), δ(ppm):10.63(s,1H,OH),5.01(d,2H,CH2),4.08(t,2H,CH2),2.51(m,1H,CH),2.20-2.11(m,3H,CH),1.90-1.45(m,11H,CH) andCH2),1.32-1.25(s,12H,CH2),0.89(m,6H,CH2).

[0043] The structural formulas of the compound of formula (III) and the grafting monomer A2 are shown below:

[0044]

[0045] Example 3: Preparation of grafted monomer.

[0046] The compound of formula (III) (20 mmol), lauryl alcohol (20 mmol) dissolved in 100 mL of tetrahydrofuran, p-toluenesulfonic acid (0.1 mmol), and hydroquinone (0.05 mmol) were added to a reaction flask, stirred, heated to 65° C., and reacted for 8 hours. The crude product was placed in a 45° C. water bath for rotary evaporation and passed through a silica gel column in an eluent of ethyl acetate: petroleum ether (v / v) = 1:10 to obtain a grafted monomer A3 with a yield of 86.8%. The NMR data were characterized as follows: 1 H-NMR(CD Cl3,400M-Hz), δ(ppm):10.60(s,1H,OH),4.98(d,2H,CH2),4.05(t,2H,CH2),2.49(m,1H,CH),2.19-2.10(m,3H,CH),1.88-1.44(m,11H,CHand CH2),1.30-1.23(s,16H,CH2),0.87(m,6H,CH2).

[0047] The structural formulas of the compound of formula (III) and the grafting monomer A3 are shown below:

[0048]

[0049] Preparation of functionalized propylene-based elastomers:

[0050] Table 1. Composition of functionalized propylene-based elastomers in parts by weight.

[0051]

[0052]

[0053] Preparation of functionalized propylene-based elastomer: According to Table 1, propylene-based elastomer resin, maleic anhydride monomer, grafting monomer, initiator, crosslinking inhibitor, and anti-sticking agent were added to a mixer and mixed uniformly. The mixture was then added to an extruder via a main feed. The initiator was added to the extruder via a side feed. The mixture was extruded at an extrusion temperature of 80°C to 220°C, a screw speed of 200 to 400 r / min, and an extrusion residence time of 30 to 60 seconds to obtain a functionalized propylene-based elastomer.

[0054] Performance test: The performance test results of the functionalized propylene-based elastomer are shown in Table 2.

[0055] Shore hardness test: Tested in accordance with standard GB / T 2411-2008.

[0056] Pendulum impact strength: measured in accordance with the method specified in GB / T 8809-2015.

[0057] Yellowing resistance test: The test was conducted by accelerating yellowing at high temperature (the functionalized propylene-based elastomers of Examples 4-6 and Comparative Examples 1-7 were respectively placed in an oven at 180°C and baked for 12 hours, and the degree of yellowing was observed. The degree of yellowing was represented by a yellowing scale of 0 to 6, where the higher the scale, the more severe the yellowing).

[0058] Table 2. Performance test results of functionalized propylene-based elastomers of Examples 4-6 and Comparative Examples 1-7.

[0059] sample Pendulum impact strength (J) Adhesion Yellowing resistance (grade) Shore hardness (D) Example 4 1.42 No adhesion 6 48 Example 5 1.40 No adhesion 6 47 Example 6 1.39 No adhesion 6 48 Comparative Example 1 0.83 No adhesion 5 35 Comparative Example 2 0.74 No adhesion 5 32 Comparative Example 3 1.39 Slight adhesion 6 45 Comparative Example 4 1.40 Slight adhesion 6 46 Comparative Example 5 1.37 Slight adhesion 6 47 Comparative Example 6 1.38 Severe adhesions 6 46 Comparative Example 7 1.41 Slight adhesion 6 47

[0060] As can be seen from Table 2, the functionalized propylene-based elastomer prepared in the present invention has the advantages of no yellowing and adhesion, and high impact strength.

[0061] Comparative Example 8: Preparation of ordinary propylene-based elastomer.

[0062] No maleic anhydride monomer and grafting monomer were added, and the remaining steps were the same as in Example 4.

[0063] Preparation of functionalized propylene-based elastomer-modified PP films according to Examples 7-9 and Comparative Examples 9-10: 85 kg of polypropylene masterbatch and 5 kg of the functionalized propylene-based elastomer of Examples 4-6 or Comparative Examples 1-2 were weighed respectively, added to a screw extruder at 180°C, blended and melted, and then extruded through a casting die to obtain a functionalized propylene-based elastomer-modified PP film. The film was heated to 110°C, and then stretched transversely and longitudinally at 120-170°C. After stretching, the film was cooled to 20°C within 10 seconds to obtain a functionalized propylene-based elastomer-modified PP film.

[0064] Comparative Example 11 Preparation of propylene-based elastomer-modified PP film: 85 kg of polypropylene masterbatch and 10 kg of propylene-based elastomer of Comparative Example 8 were weighed separately, added into a screw extruder at 180°C for blending and melting, and then extruded through a casting die to obtain a functionalized propylene-based elastomer-modified PP film. The film was heated to 110°C, and sequentially stretched transversely and longitudinally. After stretching, the film was cooled to 20°C within 10 seconds to obtain a propylene-based elastomer-modified PP film.

[0065] Performance test: The performance test results of the functionalized propylene elastomer modified PP film are shown in Table 3.

[0066] Pendulum impact strength: measured in accordance with the method specified in GB / T 8809-2015.

[0067] Yellowing resistance test: The yellowing resistance test was conducted by accelerating the yellowing at high temperature (the functionalized propylene elastomer-modified PP films of Examples 7-9 and Comparative Examples 9-11 were placed in an oven at 180°C for 12 hours, and the degree of yellowing was observed. The degree of yellowing was expressed on a scale of 0 to 6, with the higher the number, the more severe the yellowing).

[0068] Low temperature resistance test: The films prepared in Examples 7-9 and Comparative Examples 9-11 were placed in a low temperature box (-40°C) for 24 hours, and the pendulum impact strength of the films prepared in Examples 7-9 and Comparative Examples 9-11 was tested.

[0069] Haze test: Measured according to the method specified in GB / T 2410-2008.

[0070] Table 3. Performance test results of the films prepared in Examples 7-9 and Comparative Examples 9-11.

[0071] sample Impact strength (J) Yellowing resistance (grade) Low temperature resistance (J) Haze (%) Example 7 1.28 6 1.02 1.5 Example 8 1.27 6 1.01 1.6 Example 9 1.29 6 1.03 1.4 Comparative Example 9 0.71 5 0.49 1.8 Comparative Example 10 0.65 5 0.41 2.2 Comparative Example 11 1.27 5 1.00 4.3

[0072] As can be seen from Table 3, by comparing Examples 7-9 and Comparative Example 11, it can be seen that Comparative Example 11 uses a propylene-based elastomer that is not modified with a grafted monomer and maleic anhydride to modify the PP film. The amount of propylene-based elastomer in Comparative Example 11 is twice the amount of the functionalized propylene-based elastomer in Examples 7-9. The PP films prepared in Examples 7-9 and Comparative Example 11 have similar impact strength and low-temperature resistance, but the PP film of Comparative Example 11 has a larger haze.

[0073] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in the relevant field should understand that after reading the specification of this application, technicians can still modify or replace the specific implementation methods of the present invention with equivalents, but these modifications or changes do not depart from the scope of protection of the pending claims of the present application.

Claims

1. A functionalized propylene-based elastomer, characterized in that The functionalized propylene-based elastomer comprises the following raw materials in parts by weight: 64.5-80 parts of propylene-based elastomer resin, 0.2-2.13 parts of maleic anhydride monomer, 0.3-1.83 parts of grafting monomer, 0.01-1.5 parts of initiator, 0.05-1.5 parts of crosslinking inhibitor, and 2-10 parts of anti-sticking agent, wherein the grafting monomer contains a carbon-carbon double bond, a carboxyl substituent, an alicyclic structure, and a C8-C12 carbon chain structure; The structural formula of the grafting monomer is shown in formula (I): Wherein, R is a C8~C12 alkane substituent; The anti-sticking agent is selected from silicone, hydrogen fluorine silicone oil and ethylene bisstearamide in a weight ratio of 1:2-3:5-6.

2. The functionalized propylene-based elastomer according to claim 1, wherein The structural formula of the grafted monomer is shown in formula (II): 。 3. The functionalized propylene-based elastomer according to claim 1, wherein The initiator includes at least one of 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane, 1,1-bis(tert-butylperoxy)3,3,5-trimethylcyclohexane, triphenylmethane-4,4',4''-triisocyanate, diisopropyl peroxide, dibenzoyl peroxide, bis(2-tert-butylperoxyisopropyl)benzene, tert-butylisopropyl peroxide, di-tert-butyl peroxide, tert-amyl peroxybenzoate, di-tert-amyl peroxide, tert-butyl peroxybenzoate, tert-butyl peroxy-2-ethylhexanoate, tert-butyl peroxy-3,5,5-trimethylhexanoate, di(2,4-dichlorobenzoyl)peroxide, and tert-butyl peroxy-2-ethylhexyl carbonate.

4. The functionalized propylene-based elastomer according to claim 1, wherein The cross-linking inhibitor includes at least one of triphenyl phosphite, caprolactam, and stearamide.

5. The functionalized propylene-based elastomer according to any one of claims 1 to 4, wherein The preparation method of the grafting monomer comprises the following steps: The compound of formula (III), a C8-C12 alkyl alcohol dissolved in a solvent, a strong acid catalyst, and a polymerization inhibitor are mixed, the temperature is raised to react, and the crude product is separated and purified to obtain a graft monomer; The structural formula of the compound of formula (III) is shown below: 。 6. The functionalized propylene-based elastomer according to claim 5, wherein The molar ratio of the compound of formula (III) to the C8-C12 alkyl alcohol is 1:

1.

7. The functionalized propylene-based elastomer according to claim 5, wherein The strong acid catalyst includes at least one of p-toluenesulfonic acid, methanesulfonic acid, boron trifluoride etherate, scandium trifluoromethanesulfonate, and yttrium trifluoromethanesulfonate; the polymerization inhibitor includes at least one of hydroquinone, methyl hydroquinone, tert-butyl hydroquinone, 2,6-di-tert-butyl hydroquinone, N,N'-diphenyl-p-phenylenediamine, phenothiazine, and N-nitroso-cyclohexylhydroxylamine.

8. A method for preparing a functionalized propylene-based elastomer according to any one of claims 1 to 7, characterized in that: The steps include: According to parts by weight, propylene-based elastomer resin, maleic anhydride monomer, grafting monomer, initiator, crosslinking inhibitor and anti-sticking agent are added to a mixer and mixed evenly, and then added to an extruder through a main feed, and the mixture is extruded to obtain a functionalized propylene-based elastomer.

9. The method for preparing a functionalized propylene-based elastomer according to claim 8, wherein: The extrusion temperature is 80°C-220°C, the screw speed of the extruder is 200-400 r / min, and the extrusion residence time is 30-60S.

10. Use of the functionalized propylene-based elastomer according to any one of claims 1 to 7 in the preparation of polypropylene films or in functional polypropylene particles, characterized in that: The functional polypropylene particles are prepared from polypropylene, polyethylene and functionalized propylene-based elastomer in a mass ratio of 55:40:5.

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