Low-addition high-toughness POE / PP composite material and preparation method thereof

Abstract

The invention discloses a low-addition high-toughness POE (Polyolefin Elastomer) / PP (Polypropylene) composite material, which is prepared from the following components in percentage by mass: 82.5 percent to 99 percent of PP, 0.1 percent to 15 percent of POE (Polyolefin Elastomer), 0.03 percent to 0.07 percent of 2, 5-dimethyl-2, 5-bis (tert-butylperoxy) hexane, 0.8 percent to 1.5 percent of trimethylolpropane triacrylate and 0.1 percent to 0.2 percent of zinc diethyldithiocarbamate. The invention also provides a preparation method of the low-addition high-toughness POE / PP composite material. The in-situ co-branching reaction is introduced in the melting processing process, so that the compatibility between the POE and the recycled PP is improved, the toughening effect of the POE is fully exerted, the addition amount of the POE is reduced, and the negative effect of excessive addition of the POE on the strength of the recycled PP is avoided; according to the present invention, the notch impact strength of the recovered PP added with the 15% POE is increased from 6.2 kJ / m < 2 > to 40.5 kJ / m < 2 >, and is increased by more than 6 times, and the tensile strength and the bending strength basically remain unchanged, such that the efficient toughening of the recovered PP is achieved, and the high-quality re-application of the recovered PP can be economically and conveniently achieved.

Description

Technical Field

[0001] The invention belongs to the technical field of recycling and cyclic utilization of waste plastics, and specifically relates to a low-additive and high-toughness POE / PP composite material and a preparation method thereof. Background Art

[0002] As an environmentally friendly alternative to traditional PP, recycled PP can reduce dependence on oil resources, alleviate environmental pressure, and to a certain extent achieve a plastic circular economy, and has received increasing attention. However, the low market value and complex composition of recycled waste plastics make it difficult to accurately sort out PP, resulting in impure recycled PP materials and large differences in performance. In addition, the recycled waste PP will also have poorer performance than new materials due to aging and degradation, especially low toughness and poor impact strength.

[0003] By introducing POE elastomer into PP resin material, the strain of the matrix is ​​released by the hollowing of POE itself, the yield stress of the matrix is ​​reduced, and the shear yield of the matrix is ​​promoted, which is a simple and effective way to toughen PP resin material, such as the preparation method of a POE toughened PP composite material disclosed in patent (CN106317626A). However, the interface interaction between POE and PP is weak, and the particle size of POE dispersed phase is not well controlled, resulting in low POE toughening efficiency, large loss of composite material rigidity and strength, etc. In order to improve this problem, researchers used dynamic vulcanization technology to prepare high-impact POE / PP composite materials in the early years (Plastic Industry, 2008, 6: 110-115), but PP will also degrade during the dynamic vulcanization process, which has a negative effect on the material impact strength and reduces the toughening efficiency of POE. To improve this method, the researchers (Journal of Ludong University, 2018, 34: 64-68) first prepared PP / POE thermoplastic elastomer (TPV) using dynamic vulcanization technology. The TPV has good compatibility with PP, and then used it to toughen PP. When the mass ratio of TPV to PP was 2:3 and 1:1, respectively, the impact strength of the composite material increased from 2.8 kJ / m 2 Increase to 20.0kJ / m 2 and 47.4 kJ / m 2 However, the tensile strength of the composite material is reduced from 33.6MPa to 23.1MPa and 19.1MPa. That is, in the prior art, in order to achieve a good toughening effect, the amount of elastomer added to the POE material is too much, resulting in a large loss of strength and the inability to achieve a simultaneous increase in toughness and strength. Summary of the invention

[0004] The present invention aims to solve one of the technical problems in the related art to at least a certain extent. To this end, the main purpose of the present invention is to provide a low-addition high-toughness POE / PP composite material, which aims to solve the problem that the toughness and strength of the existing POE / PP material cannot grow synchronously or even inverted. The present invention also provides a preparation method of the low-addition high-toughness POE / PP composite material.

[0005] The objective of the present invention is achieved through the following technical solutions:

[0006] A low-addition high-toughness POE / PP composite material comprises, by mass percentage, 85%-99% of PP, 0.1%-15% of POE, 0.03%-0.07% of 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane, 1%-1.5% of trimethylolpropane triacrylate and 0.1%-0.2% of zinc diethyldithiocarbamate.

[0007] In some specific embodiments, the PP is waste recycled PP, and its melting index at 230°C and 2.16kg is 10-20g / 10min; the melting index of the POE at 190°C and 2.16kg is 1-5g / 10min.

[0008] A method for preparing the aforementioned low-addition high-toughness POE / PP composite material comprises the following steps:

[0009] 1) according to the formula requirements, 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane, trimethylolpropane triacrylate and zinc diethyldithiocarbamate are mixed and dissolved to obtain a mixed solution;

[0010] 2) spraying the mixed solution obtained in step 1) uniformly on the surface of the dried mixed resin composed of POE and PP to obtain a modified mixed resin;

[0011] 3) adding the modified mixed resin obtained in step 2) into a twin-screw extruder to extrude into strips, pelletize and dry to obtain a POE / PP composite material.

[0012] In some specific embodiments, the drying temperature of POE and PP in step 2) is 80-100° C. and the drying time is 2-6 hours.

[0013] Furthermore, in step 2), the drying temperature of POE and PP is 85-95° C. and the drying time is 3-5 hours.

[0014] In some specific embodiments, the temperature of the twin-screw extruder in step 2) is: zone 1 is 160-170°C, zone 2 is 170-190°C, zone 3 is 180-200°C, zone 4 is 180-200°C, zone 5 is 180-200°C, zone 6 is 170-190°C, the main engine speed is 150-250r / min, and the feeding speed is 8-15r / min.

[0015] Furthermore, the temperature of the twin-screw extruder in step 2) is: 170°C in zone 1, 180°C in zone 2, 200°C in zone 3, 200°C in zone 4, 200°C in zone 5, 190°C in zone 6, the main engine speed is 150r / min, and the feeding speed is 8r / min.

[0016] Compared with the prior art, the present invention has at least the following advantages:

[0017] The low-addition high-toughness POE / PP composite material provided by the present invention improves the compatibility between POE and recycled PP by introducing an in-situ co-branching reaction during the melt processing, gives full play to the toughening effect of POE, reduces the addition amount of POE, and avoids the negative effect of excessive addition of POE on the strength of recycled PP; the notched impact strength of the recycled PP with 15% POE added is increased from 6.2 kJ / m 2 Increased to 40.5 kJ / m 2 , increased by more than 6 times, while the tensile strength and flexural strength remain basically unchanged; the POE / PP composite material obtained by the preparation method of the present application, compared with the prior art, reduces the amount of POE by more than half, and obtains a POE / PP composite material with the same level of impact strength; the present invention realizes the efficient toughening of recycled PP, and can economically and conveniently realize the high-quality reuse of recycled PP. DETAILED DESCRIPTION

[0018] The present invention will be further described in detail below in conjunction with specific embodiments. The following embodiments are merely illustrative and not restrictive, and the protection scope of the present invention cannot be limited thereto.

[0019] When a certain amount, concentration or other value or parameter is expressed in the form of a range, a preferred range, or a preferred upper and lower numerical limit, it should be understood that it is equivalent to specifically revealing any range by combining any pair of upper range limits or preferred numerical values ​​with any lower range limit or preferred numerical value, regardless of whether the range is specifically disclosed. Unless otherwise indicated, the numerical range values ​​listed herein include the endpoints of the range, and all integers and fractions within the range.

[0020] Unless otherwise indicated, all percentages, parts, ratios, etc. herein are by weight.

[0021] The materials, methods, and examples herein are illustrative and are not to be construed as limiting unless specifically stated.

[0022] In the following embodiments, the POE used in the present invention is Korean LG170, and its melt index at 190°C and 2.16kg is 1.1g / 10min; the recycled PP is provided by Foshan Guston Plastic Products Co., Ltd., and its melt index at 230°C and 2.16kg is 17.8g / 10min; DHBP, TMPATA and ZDEC are analytically pure products of Aladdin Reagent Co., Ltd.

[0023] Example 1

[0024] This embodiment provides a method for preparing a low-additive high-toughness POE / PP composite material, which comprises the following steps:

[0025] 1) Dry the mixed resin of POE and PP at 80°C for 2h;

[0026] 2) weighing raw materials, and the composite material comprises, by mass percentage, 88.97% of PP, 10% of POE, 0.03% of 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane, 0.9% of trimethylolpropane triacrylate and 0.1% of zinc diethyldithiocarbamate;

[0027] 3) according to the formula requirements, 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane, trimethylolpropane triacrylate and zinc diethyldithiocarbamate are mixed and dissolved to obtain a mixed solution;

[0028] 4) spraying the mixed solution obtained in step 3) uniformly on the surface of the mixed resin composed of PP and POE after drying to obtain a modified mixed resin;

[0029] 5) adding the modified mixed resin obtained in step 4) into a twin-screw extruder, and extruding into strips according to the set temperatures: zone 1 170°C, zone 2 180°C, zone 3 200°C, zone 4 200°C, zone 5 200°C, zone 6 190°C, main engine speed 150r / min, feed speed 8r / min, and successively water cooling, drying, pelletizing and drying to obtain a POE / PP composite material.

[0030] Example 2

[0031] This embodiment provides a method for preparing a low-additive high-toughness POE / PP composite material, which comprises the following steps:

[0032] 1) Dry the mixed resin of POE and PP at 80°C for 2h;

[0033] 2) weighing raw materials, and the composite material comprises, by mass percentage, 88.63% of PP, 10% of POE, 0.07% of 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane, 1.2% of trimethylolpropane triacrylate and 0.1% of zinc diethyldithiocarbamate;

[0034] 3) according to the formula requirements, 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane, trimethylolpropane triacrylate and zinc diethyldithiocarbamate are mixed and dissolved to obtain a mixed solution;

[0035] 4) spraying the mixed solution obtained in step 3) uniformly on the surface of the mixed resin composed of PP and POE after drying to obtain a modified mixed resin;

[0036] 5) adding the modified mixed resin obtained in step 4) into a twin-screw extruder, and extruding into strips according to the set temperatures: zone 1 170°C, zone 2 180°C, zone 3 200°C, zone 4 200°C, zone 5 200°C, zone 6 190°C, main engine speed 150r / min, feed speed 8r / min, and successively water cooling, drying, pelletizing and drying to obtain a POE / PP composite material.

[0037] Example 3

[0038] This embodiment provides a method for preparing a low-additive high-toughness POE / PP composite material, which comprises the following steps:

[0039] 1) Dry the mixed resin of POE and PP at 80°C for 2h;

[0040] 2) weighing raw materials, and the composite material comprises, by mass percentage, 83.63% of PP, 15% of POE, 0.07% of 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane, 1.2% of trimethylolpropane triacrylate and 0.1% of zinc diethyldithiocarbamate;

[0041] 3) according to the formula requirements, 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane, trimethylolpropane triacrylate and zinc diethyldithiocarbamate are mixed and dissolved to obtain a mixed solution;

[0042] 4) spraying the mixed solution obtained in step 3) uniformly on the surface of the mixed resin composed of PP and POE after drying to obtain a modified mixed resin;

[0043] 5) adding the modified mixed resin obtained in step 4) into a twin-screw extruder, and extruding into strips according to the set temperatures: zone 1 170°C, zone 2 180°C, zone 3 200°C, zone 4 200°C, zone 5 200°C, zone 6 190°C, main engine speed 150r / min, feed speed 8r / min, and successively water cooling, drying, pelletizing and drying to obtain a POE / PP composite material.

[0044] Comparative Example 1

[0045] The materials provided in this comparative example have substantially the same components and proportions as those in Example 3, except that POE is not added; and the method steps are the same as those in Example 3.

[0046] Comparative Example 2

[0047] The materials provided in this comparative example have substantially the same components and proportions as those in Example 3, except that DHBP, TMPTA and ZDEC are not added; and the method steps are the same as those in Example 3.

[0048] Comparative Example 3

[0049] The materials provided in this comparative example have substantially the same components and proportions as those in Example 3, except that DHBP, TMPTA, ZDEC and POE are not added; and the method steps are the same as those in Example 3.

[0050] Performance Test:

[0051] The present application conducts performance tests on the POE / recycled PP composite materials provided in Examples 1-3 and Comparative Examples 1-3, wherein: in order to test the mechanical properties of the composite materials, standard test specimens are injection molded by an injection molding machine, the injection molding temperature is 180-200°C, and the injection molding pressure is 45-65MPa; the preparation conditions of the test specimens in each embodiment and comparative example are the same.

[0052] The tensile properties of the composite materials were tested according to GB / T1040-1992, the flexural properties of the composite materials were tested according to GB / T9341-200, and the impact strength of the composite materials was tested according to GB / T1843-2008. The specific test results are shown in Table 1.

[0053] Table 1 Performance test results of POE / PP composite materials in Examples 1-3 and Comparative Examples 1-3

[0054]

[0055] Comparing Comparative Examples 2 and 3 in Table 1, it can be seen that when only 15% POE is added, the toughness of the recycled PP is improved, but at the same time, the tensile strength and flexural strength decrease significantly, which is similar to previous reports. When only the in-situ co-branching reaction is introduced (Comparative Example 1), the strength and toughness of the recycled PP are improved. This may be because the generated co-branched long-chain polymer improves the compatibility of the PP matrix in the recycled PP with the resin impurities that cannot be completely separated, thereby improving the overall performance of the recycled PP. Furthermore, when the in-situ co-branching reaction and 15% POE are introduced at the same time (Example 3), the impact strength of the prepared POE / recycled PP composite material increases from 6.2 to 40.5 kJ / m 2 , increased by more than 6.5 times, while the tensile strength and flexural strength remained basically unchanged. In addition, by comparing Examples 2-3, it can be seen that the toughness of the POE / recycled PP composite material increases with the increase of POE content, and by comparing Examples 2-3, it can be seen that the strength of the POE / recycled PP composite material increases with the increase of the degree of co-branching reaction. In summary, it is shown that the low-addition high-toughness POE / recycled PP composite material and its preparation method provided by the present invention can effectively improve the compatibility of POE and recycled PP resin, give full play to the toughening effect of POE, and reduce the addition amount of POE elastomer.

[0056] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein by equivalents. These modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention, and they should all be included in the scope of the claims and specification of the present invention.

Claims

1. A low-addition high-toughness POE / PP composite material, characterized in that: In terms of mass percentage, it comprises 82.5%-99% of PP, 0.1%-15% of POE, 0.03%-0.07% of 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane, 0.8%-1.5% of trimethylolpropane triacrylate and 0.1%-0.2% of zinc diethyldithiocarbamate.

2. The low-addition high-toughness POE / PP composite material according to claim 1, characterized in that: The PP is waste recycled PP, and its melting index at 230° C. and 2.16 kg is 10-20 g / 10 min; the melting index of the POE at 190° C. and 2.16 kg is 1-5 g / 10 min.

3. A method for preparing a low-addition high-toughness POE / PP composite material according to claim 1 or 2, characterized in that: The steps include: 1) according to the formula requirements, 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane, trimethylolpropane triacrylate and zinc diethyldithiocarbamate are mixed and dissolved to obtain a mixed solution; 2) spraying the mixed solution obtained in step 1) uniformly on the surface of the dried mixed resin composed of POE and PP to obtain a modified mixed resin; 3) adding the modified mixed resin obtained in step 2) into a twin-screw extruder to extrude into strips, pelletize and dry to obtain a POE / PP composite material.

4. The method for preparing the low-addition high-toughness POE / PP composite material according to claim 4, characterized in that: In the step 2), the drying temperature of POE and PP is 80-100° C. and the drying time is 2-6 hours.

5. The method for preparing the low-addition high-toughness POE / PP composite material according to claim 4, characterized in that: In the step 2), the drying temperature of POE and PP is 85-95° C. and the drying time is 3-5 hours.

6. The method for preparing the low-addition high-toughness POE / PP composite material according to claim 1, characterized in that: The temperature of the twin-screw extruder in step 2) is: 160-170°C in zone 1, 170-190°C in zone 2, 180-200°C in zone 3, 180-200°C in zone 4, 180-200°C in zone 5, 170-190°C in zone 6, the main engine speed is 150-250r / min, and the feeding speed is 8-15r / min.

7. The method for preparing a low-addition high-toughness POE / PP composite material according to claim 1, characterized in that: The temperature of the twin-screw extruder in step 2) is: 170°C in zone 1, 180°C in zone 2, 200°C in zone 3, 200°C in zone 4, 200°C in zone 5, 190°C in zone 6, the main engine speed is 150r / min, and the feeding speed is 8r / min.

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