阅读说明：本技术 一种高熔接痕强度玻纤增强聚丙烯复合材料及其制备方法 (High weld mark strength glass fiber reinforced polypropylene composite material and preparation method thereof ) 是由 陈大华 谭寿再 陈金伟 何亮 刘青山 于 2019-09-30 设计创作，主要内容包括：本发明提供了一种高熔接痕强度玻纤增强聚丙烯复合材料,按重量份计,包括以下组分：均聚聚丙烯100份；马来酸酐接枝聚丙烯1-10份；PA6 1-10份；玻璃纤维1-50份；其中,PA6的分子量范围是5000-10000。本发明通过在均聚丙烯中加入一定量特定分子量范围的PA6,能够提升玻纤增强聚丙烯的熔接线强度。(The invention provides a high weld mark strength glass fiber reinforced polypropylene composite material, which comprises the following components in parts by weight: 100 parts of homopolymerized polypropylene; 1-10 parts of maleic anhydride grafted polypropylene; PA 61-10 parts; 1-50 parts of glass fiber; wherein, the molecular weight range of PA6 is 5000-10000. According to the invention, a certain amount of PA6 with a specific molecular weight range is added into the homopolymerized polypropylene, so that the weld line strength of the glass fiber reinforced polypropylene can be improved.)

1. The glass fiber reinforced polypropylene composite material with high weld mark strength is characterized by comprising the following components in parts by weight:

100 parts of homopolymerized polypropylene;

1-10 parts of maleic anhydride grafted polypropylene;

PA 61-10 parts;

1-50 parts of glass fiber;

wherein, the molecular weight range of PA6 is 5000-10000, and the grafting rate of maleic anhydride grafted polypropylene is 0.7-2%.

2. The high weld mark strength glass fiber reinforced polypropylene composite material as claimed in claim 1, which comprises the following components in parts by weight:

100 parts of homopolymerized polypropylene;

2-7 parts of maleic anhydride grafted polypropylene;

PA 62-7 parts;

1-50 parts of glass fiber.

3. The high weld mark strength glass fiber reinforced polypropylene composite material as claimed in claim 1 or 2, wherein the melt flow rate of the homopolymerized polypropylene is 10-40 g/10min, 2.13kg/230 ℃, and the test method is GB/T3682.1-2018.

4. The high weld mark strength glass fiber reinforced polypropylene composite material as claimed in claim 1 or 2, wherein the melt flow rate of the maleic anhydride grafted polypropylene is 50-200 g/10min, 2.13kg/230 ℃, and the test method is GB/T3682.1-2018.

5. The high weld mark strength glass fiber reinforced polypropylene composite material as claimed in claim 1 or 2, further comprising 0-3 parts by weight of an antioxidant.

6. The method for preparing the high weld mark strength glass fiber reinforced polypropylene composite material as claimed in any one of claims 1 to 5, which is characterized by comprising the following steps: according to the proportion, homo-polypropylene, maleic anhydride grafted polypropylene, PA6 and an antioxidant are fed from a main feeding port, glass fiber is fed from a side feeding port, and the glass fiber reinforced polypropylene composite material with high weld mark strength is obtained through extrusion and granulation of a double-screw extruder, wherein the extrusion temperature is set to be 180-230 ℃, the rotation speed of a main machine screw is 300-600 rpm, and the length-diameter ratio of the screw is 40: 1.

Technical Field

The invention relates to the technical field of high polymer materials, in particular to a glass fiber reinforced polypropylene composite material with high weld mark strength and a preparation method thereof.

Background

After the polypropylene is reinforced by the glass fiber, the strength, rigidity, impact strength and thermal deformation temperature of the polypropylene can be greatly improved, so that the polypropylene can be widely applied to industries such as automobiles, building materials, household appliances and the like. However, during application, weld mark locations of injection molded articles of reinforced polypropylene are often found to be the initiation points of failure of the articles. This is because the addition of glass fiber can greatly improve the strength of the material, but it is difficult to improve the weld mark strength. In general, the strength of the glass fiber reinforced weld mark is not higher than that of the matrix resin, which is mainly caused by poor compatibility between the glass fiber and the resin matrix, and even if the glass fiber is modified to improve the compatibility between the glass fiber and the resin matrix, the improvement on the strength of the weld line is insufficient; furthermore, the weld mark strength is difficult to be improved by merely adding maleic anhydride grafted polypropylene to increase the compatibility. The glass fiber reinforced polypropylene material with high weld mark strength can be used for preparing lighter and lower-cost parts, so that the weld mark strength of the glass fiber reinforced polypropylene material is urgently required to be improved in order to further expand the application of the glass fiber reinforced polypropylene material and reduce the cost.

CN200810218925.8 discloses a high weld mark strength reinforced polypropylene material and a preparation method thereof, in the patent, the weld mark strength is improved by reducing the orientation of glass fibers to improve the bridging level of the glass fibers to an interface.

CN 201510900503.9-A polyamide material with enhanced weld mark strength, its preparation method and application are disclosed, wherein the weld mark strength is improved by adding a polyamide copolymer, specifically, the polyamide copolymer is obtained by condensation polymerization reaction of dicarboxylic acid and diamine, or ring-opening polymerization of lactam. However, the polyamide copolymer is exemplified only by PA6I/6T (a polymer of adipic acid and isophthalic acid/a block copolymer of a polymer of adipic acid and terephthalic acid) in the description, and the viscosity thereof is preferably selected. Meanwhile, the description does not describe a mechanism, and it is possible to increase the entanglement level between the resin molecules.

Disclosure of Invention

The invention aims to provide a high-weld mark strength glass fiber reinforced polypropylene composite material which is prepared by adding a certain amount of PA6 and maleic anhydride grafted polypropylene into a formula for compounding.

The glass fiber reinforced polypropylene composite material with high weld mark strength comprises the following components in parts by weight:

100 parts of homopolymerized polypropylene;

1-10 parts of maleic anhydride grafted polypropylene;

PA 61-10 parts;

1-50 parts of glass fiber;

wherein, the molecular weight range of PA6 is 5000-10000, and the grafting ratio of the maleic anhydride grafted polypropylene is 0.7-2%.

Preferably, the composition comprises the following components in parts by weight:

100 parts of homopolymerized polypropylene;

2-7 parts of maleic anhydride grafted polypropylene;

PA 62-7 parts;

1-50 parts of glass fiber.

Preferably, the melt flow rate of the homopolymerized polypropylene is 10-40 g/10min, the melt flow rate is 2.13kg/230 ℃, and the test method is GB/T3682.1-2018.

Experiments show that when a small amount (less than 10%) of low molecular weight PA6 (molecular weight 5000-10000) is added to the glass fiber reinforced polypropylene, the weld mark strength of the material is improved more. The reason for this is that the PA6 with low molecular weight is enriched at the front end of the melt flow, and the amido bonds form hydrogen bonds, thereby greatly increasing the intermolecular force at the weld mark and improving the weld mark strength. However, as the content of PA6 is further increased, its compatibility with PP deteriorates faster. There is therefore an optimum range for the amount of low molecular weight PA6 used.

The grafting rate of the maleic anhydride grafted polypropylene is 0.7-2%, the melt flow rate is 50-200 g/10min and 2.13kg/230 ℃, and the test method is GB/T3682.1-2018. Generally, the grafting rate of the common maleic acid glycoside grafted polypropylene is in the range of 0.3-3.5%, and also exceeds 5% and even reaches 10% by customization, however, the invention finds that the improvement of the weld line strength of the glass fiber reinforced polypropylene material is only obvious if the grafting rate is in a small range of 0.7-2% through experiments.

Not all polyamides having molecular weights within the above range can achieve the improvement of weld mark strength, and PA66, PA10T, PA12, PA6, PA1010 and the like are tested, and the improvement of weld mark strength is extremely limited, and even the weld mark strength may be reduced due to compatibility problems.

0-3 parts of antioxidant is also included according to the parts by weight.

Antioxidants include primary antioxidants or stabilizers (e.g., hindered phenols and/or secondary arylamines.) suitable antioxidants include alkylated monophenols or polyphenols, alkylation reaction products of polyphenols with dienes such as tetrakis [ methylene (3, 5-di-tert-butyl-4-hydroxyhydrocinnamate) ] methane and the like, butylated reaction products of p-cresol or dicyclopentadiene, alkylated hydroquinones, hydroxylated thiodiphenyl ethers, alkylidene bisphenols, benzyl compounds, β esters of (3, 5-di-tert-butyl-4-hydroxyphenyl) -propionic acid with a monohydric or polyhydric alcohol, esters of β - (5-tert-butyl-4-hydroxy-3-methylphenyl) -propionic acid with a monohydric or polyhydric alcohol, esters of sulfanyl or thioaryl compounds such as distearyl thiopropionate, dilauryl thiopropionate, ditridecyl thiopropionate, octadecyl-3- (3, 5-di-tert-butyl-4-hydroxyphenyl) propionate, pentaerythritol-tetrakis [3- (3, 5-di-tert-butyl-4-hydroxyphenyl) ] propionate and the like, β - (3, 5-di-tert-butyl-4-hydroxyphenyl) -propionate and the like, or combinations comprising at least one of the foregoing antioxidants.

Of course, auxiliary agents such as lubricants and the like can be added for improving the processing adjustment of the composite material, and some ultraviolet resistant agents, high-temperature stabilizers and the like can be added for improving other weather resistance.

The preparation method of the glass fiber reinforced polypropylene composite material with high weld mark strength comprises the following steps: according to the proportion, homo-polypropylene, maleic anhydride grafted polypropylene, PA6 and an antioxidant are fed from a main feeding port, glass fiber is fed from a side feeding port, and the glass fiber reinforced polypropylene composite material with high weld mark strength is obtained through extrusion and granulation of a double-screw extruder, wherein the extrusion temperature is set to be 180-230 ℃, the rotation speed of a main machine screw is 300-600 rpm, and the length-diameter ratio of the screw is 40: 1.

Compared with the prior art, the invention has the following beneficial effects

In general, in the prior art, a certain amount of maleic anhydride grafted polypropylene is added into glass fiber reinforced polypropylene to improve the strength (tensile strength and bending strength), but the weld mark strength cannot be improved. According to the invention, a certain amount of PA6 and maleic anhydride grafted polypropylene with specific molecular weight range are added into the homopolymerized propylene, so that the weld line strength of the polypropylene glass fiber reinforcing agent can be improved, and the low molecular weight PA6 is enriched at the front end of the melt flow, and the amido bonds form hydrogen bonds, so that the intermolecular force at the weld mark is greatly increased, and the weld mark strength is improved.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is further described in detail with reference to the following claims and specific examples. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

The examples of the invention and the comparative examples used the following raw materials:

homo-polypropylene: the petrochemical PP N-Z30S has MFR of 25g/10 min;

copolymerized polypropylene: korea SK chemical PP BX3800, MFR 27g/10 min;

maleic anhydride-grafted polypropylene a: the grafting rate is 1.8 percent, and the melt flow rate is 80g/10 min;

maleic anhydride grafted polypropylene B: the grafting rate is 0.8 percent, and the melt flow rate is 89g/10 min;

maleic anhydride-grafted polypropylene C: the grafting rate is 0.3 percent, and the melt flow rate is 102g/10 min;

maleic anhydride-grafted polypropylene D: the grafting rate is 3.5 percent, and the melt flow rate is 72g/10 min;

maleic anhydride grafted polyethylene: the grafting rate was 1.3%, and the melt flow rate was 98g/10 min.

PA 6-A: a molecular weight of about 6000;

PA 6-B: a molecular weight of about 9000;

PA 6-C: a molecular weight of about 3000;

PA 6-D: a molecular weight of about 20000;

PA 66: a molecular weight of about 8000;

PA 10T: a molecular weight of about 10000;

glass fiber: CPIC ECS 305K;

antioxidant: hindered phenol antioxidants;