A glass fiber reinforced polypropylene material and its preparation method and application

Abstract

The present invention discloses a glass fiber reinforced polypropylene material, a preparation method thereof, and an application thereof. The glass fiber reinforced polypropylene material of the present invention comprises the following components, by weight: 60 to 80 parts of polypropylene resin, 20 to 40 parts of glass fiber, 0.3 to 3 parts of copolymer, and 0.2 to 2 parts of stearate lubricant; the copolymer is one or more of ethylene-acrylic acid copolymer, ethylene-methacrylic acid copolymer, and ethylene-methacrylic acid-acrylic acid copolymer. The glass fiber reinforced polypropylene material of the present invention utilizes the separation effect of glass fiber and resin at the melt flow front of the composite material to improve welding performance. By using a special copolymer as a compatibilizer to regulate the degree of separation of glass fiber and resin at the melt flow front, and using a special lubricant to promote the bonding of the melt during the welding process, the good mechanical properties of the glass fiber reinforced polypropylene material are maintained while significantly improving its hot plate welding performance.

Description

Technical Field

[0001] The present invention relates to the technical field of polymer compound compositions, and more particularly to a glass fiber reinforced polypropylene material, a preparation method thereof, and an application thereof. Background Art

[0002] Polypropylene is one of the most commonly used general-purpose plastics, widely used in consumer goods, automobiles, home appliances, and other fields. In the automotive sector, in particular, with the trend toward lightweight vehicles, replacing steel with plastic has become a hot research topic in automotive parts. However, pure polypropylene suffers from insufficient rigidity, and glass fiber-modified polypropylene is often used to enhance its rigidity. However, existing glass fiber-reinforced polypropylene welding materials are prone to problems such as poor weld strength and insufficient weld surface sealing during welding, which has seriously hampered their application in welded connectors.

[0003] For the welding of thermoplastics, the process mainly includes melting and cooling. The purpose of melting is to allow polymer molecules to obtain high energy to intensify thermal motion, thereby breaking free from the attraction and weak chemical bonds between molecules inside the plastic and the binding force on the plastic surface, and moving toward the other plastic welding surface, so that different molecules are entangled with each other. Then, after cooling "freezes" the movement of plastic molecules, the internal molecules of the two plastics near the welding surface can be redistributed, and the welding is completed.

[0004] However, due to the addition of rigid, two-dimensional glass fibers in glass fiber reinforced polypropylene welding materials, the polymer macromolecules on the welding surface are restricted by the glass fibers, and the entanglement effect caused by molecular thermal motion is weakened. At the same time, the pressure direction of the welding surface is inconsistent with the orientation direction of the glass fibers. The secondary orientation of the glass fibers further restricts the diffusion movement of the polymer macromolecules on the two welding surfaces. That is, the existing glass fiber reinforced polypropylene composite materials have the problem of poor welding performance. Summary of the Invention

[0005] The purpose of the present invention is to overcome the defects and shortcomings of the existing glass fiber reinforced polypropylene composite materials with poor welding performance and to provide a glass fiber reinforced polypropylene material.

[0006] Another object of the present invention is to provide a method for preparing a glass fiber reinforced polypropylene material.

[0007] Another object of the present invention is to provide an application of the above-mentioned glass fiber reinforced polypropylene material in automobile interior and exterior trims, home appliances or electronic appliances.

[0008] The above-mentioned purpose of the present invention is achieved through the following technical solutions:

[0009] The present invention protects a glass fiber reinforced polypropylene material, which comprises the following components in parts by weight:

[0010] 60-80 parts of polypropylene resin, 20-40 parts of glass fiber, 0.3-3 parts of copolymer, and 0.2-2 parts of stearate lubricant; wherein the copolymer is one or more of ethylene-acrylic acid copolymer, ethylene-methacrylic acid copolymer, and ethylene-methacrylic acid-acrylic acid copolymer.

[0011] The polypropylene resin in the above-mentioned glass fiber reinforced polypropylene material is the matrix resin, and its mass percentage relative to the glass fiber reinforced polypropylene material is ≥50%; the average diameter of the glass fiber is preferably 8 to 15 mm; the copolymer is formed by polymerization of polyethylene (PE) and methacrylic acid and / or acrylic acid, and the polyethylene can be low-density polyethylene (LDPE), high-density polyethylene (HDPE) or medium-density polyethylene (MDPE); at the same time, research has found that compared with other polyethylenes, the molecular chain segments of linear low-density polyethylene are relatively regular, which can better regulate the content of polar segments (acrylic acid segments, methacrylic acid segments or methacrylic acid-acrylic acid segments) in the copolymer, thereby better improving the compatibility between the glass fiber and the resin, so linear low-density polyethylene is preferred.

[0012] It should also be noted that the above copolymer can be obtained by the following preparation method, or can be purchased by other methods or commercial products:

[0013] PE is dissolved in a mixed solution of xylene / ethanol (volume ratio of (40-70):(30-60)) at 40-60°C, and methacrylic acid and / or acrylic acid and initiator AIBN (azobisisobutyronitrile) are added. The mixture is then reacted at 70-90°C in an inert gas atmosphere for 4-6 hours, then the reaction is terminated, separated, and purified to obtain a copolymer. The mass percentage of the initiator relative to PE is 1% to 1.5%.

[0014] When methacrylic acid and acrylic acid are added simultaneously in the above reaction, the molar ratio of methacrylic acid to acrylic acid is (60-80):(20-40), specifically 70:30.

[0015] Optionally, the polypropylene resin has a melt index of 1 to 5 g / 10 min, specifically 1 to 2 g / 10 min, 2 to 3 g / 10 min, or 3 to 5 g / 10 min, measured at 230° C. and 2.16 kg according to GB / T 3682.2-2018.

[0016] Optionally, the polypropylene resin is one or more of homopolypropylene (PP-H), block copolymer polypropylene (PP-B) and random copolymer polypropylene (PP-R). Preferably, the polypropylene resin is homopolypropylene and / or block copolymer polypropylene, more preferably homopolypropylene.

[0017] Optionally, the mass percentage of acrylic acid in the ethylene-acrylic acid copolymer is ≥1%; or the mass percentage of methacrylic acid in the ethylene-methacrylic acid copolymer is ≥1%; or the mass percentage of total acrylic acid and methacrylic acid in the ethylene-methacrylic acid-acrylic acid copolymer is ≥1%.

[0018] The mass percentage of acrylic acid or methacrylic acid in the above copolymer can be determined by using the characteristic absorption peak of Fourier infrared (1700 cm -1 The integrated area of ​​the C=O double bond is analyzed to obtain the content of the C=O double bond, which is then calculated.

[0019] Specifically, the stearate lubricant is at least one of pentaerythritol stearate, ethylene glycol stearate, glyceryl stearate and butyl stearate; preferably pentaerythritol stearate.

[0020] Specifically, the total mass percentage of acrylic acid and methacrylic acid in the ethylene-methacrylic acid-acrylic acid copolymer is 1% to 9%, preferably 3% to 5%.

[0021] Specifically, the glass fiber reinforced polypropylene material further comprises 0.01 to 5 parts by weight of an antioxidant. Optionally, the antioxidant is one or more of a phenolic antioxidant, a phosphite antioxidant, a divalent sulfur antioxidant, and a hindered amine antioxidant.

[0022] Among them, the phenolic antioxidant is one or more of antioxidant 264, antioxidant 1010, antioxidant 1076, antioxidant SP, antioxidant 2246, antioxidant CA, antioxidant 330, Irganox 1890 and antioxidant 3114; the phosphite antioxidant is one or more of antioxidant TNP, antioxidant ODP, antioxidant 168, Irganox 1093 and Irganox 1222; the divalent sulfur antioxidant is dilauryl thiodipropionate (DLTP) and / or distearyl thiodipropionate (DSTP); and the hindered amine antioxidant is one or more of LS-744, LS-770, GW-540 and Flamstab NOR116.

[0023] In addition, the glass fiber reinforced polypropylene material of the present invention may further contain a light stabilizer and a flow modifier without impairing the effects of the present invention; the light stabilizer may be 2-hydroxy-4-n-octyloxybenzophenone, 2,2,6,6-tetramethylpiperidine and its substituted derivatives; the flow modifier may be an acrylic resin, a hyperbranched siloxane, etc.

[0024] The present invention provides a method for preparing a glass fiber reinforced polypropylene material, comprising the following steps:

[0025] The components are mixed and melt-extruded to obtain glass fiber reinforced polypropylene material.

[0026] The melt extrusion can be carried out using a twin-screw extruder, and the temperature of the melt extrusion is 180-210°C.

[0027] The application of the above-mentioned glass fiber reinforced polypropylene material in automotive interior and exterior trims, household appliances, or electronic appliances also falls within the scope of protection of the present invention. Specifically, the material can be used in automotive interior and exterior trims, household appliances, or electronic appliances with upper and lower housings or spliced ​​components. Examples include the upper and lower housings of lithium battery packs in automobiles, the housings of electrical control boxes in household appliances, and the outer casings of household water pumps.

[0028] Compared with the prior art, the present invention has the following beneficial effects:

[0029] The glass fiber reinforced polypropylene material of the present invention combines a specific copolymer with a stearate lubricant, utilizes the separation effect of glass fiber and resin at the melt flow front of the composite material to improve welding performance, uses a special compatibilizer (specific copolymer) to regulate the degree of separation of glass fiber and resin at the melt flow front, and uses a special lubricant to promote the bonding of the melt during the welding process, thereby maintaining the mechanical properties of the glass fiber reinforced polypropylene material without significant attenuation while significantly improving the hot plate welding performance of the material. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 This is an SEM image of the cross section of the glass fiber reinforced polypropylene material in Example 1.

[0031] Figure 2 This is the SEM image of the cross section of the glass fiber reinforced polypropylene material in Comparative Example 1. DETAILED DESCRIPTION

[0032] The present invention will be further described below in conjunction with specific embodiments, but the examples do not limit the present invention in any form. Unless otherwise specified, the raw materials and reagents used in the examples of the present invention are conventionally purchased raw materials and reagents.

[0033] 1. Raw materials and reagents

[0034] (1) PP-1, homopolymer polypropylene, melt index 3 g / 10 min, brand PP T30S, manufactured by PetroChina Dushanzi Petrochemical Co., Ltd.

[0035] PP-2, block copolymer polypropylene, melt index of 3g / 10min, brand PP K8003, manufacturer: PetroChina Dushanzi Petrochemical Co., Ltd.

[0036] PP-3, random copolymer polypropylene, melt index is 2g / 10min, brand PP SM198, manufacturer LOTTECHEMICAL;

[0037] Glass fiber, brand ECS-13-04-508A, manufacturer Jushi Group Co., Ltd.

[0038] PP-g-MAH, brand BONYRAM 1001CN, manufacturer Shanghai Zhuangjing Co., Ltd.

[0039] Pentaerythritol stearate (PTES), brand PETS-4, manufactured by Jiangxi Weike Oil and Fat Chemical Co., Ltd.

[0040] Butyl stearate, manufacturer: Shandong Kexing;

[0041] Calcium stearate, brand BS-3818, manufacturer: Bailihe Chemical (Zhongshan) Co., Ltd.

[0042] Ethylene bisstearamide, brand EBS B50, manufacturer Guangdong Runfeng Chemical Co., Ltd.

[0043] The processing aid is a phenolic antioxidant, brand RIANOX 1010, manufactured by Tianjin Li'anlong New Materials Co., Ltd.

[0044] (2) The copolymer can be prepared by the following preparation method, or by other preparation methods in the prior art, or by commercial purchase:

[0045] At 50°C, LLDPE is dissolved in a mixed solution of xylene / ethanol (volume ratio of 50:50), and then the reaction monomer and initiator AIBN (azobisisobutyronitrile) are added; then, the reaction is terminated after reacting at 80°C in an inert gas atmosphere for 4 hours; finally, the mixture is precipitated in ice ether, washed, and dried to obtain ethylene-methacrylic acid-acrylic acid copolymer (E-MAA-AA), ethylene-methacrylic acid copolymer (E-MAA), or ethylene-acrylic acid copolymer (E-AA).

[0046] The LLDPE used in the reaction is LLDPE 7042, manufactured by Maoming Petrochemical. The monomers used are methacrylic acid, acrylic acid, or a mixture of methacrylic acid and acrylic acid (with a molar ratio of methacrylic acid to acrylic acid of 70:30). By adjusting the mass ratio of the monomers to LLDPE, copolymers with varying acrylic acid or methacrylic acid contents can be obtained. The initiator dosage is generally 1% to 1.5% of the PE mass. The AIBN dosage is 1.3% of the LLDPE mass.

[0047] a. Terpolymer:

[0048] E-MAA-AA-1, the total mass percentage of methacrylic acid and acrylic acid is 3%;

[0049] E-MAA-AA-2, the total mass percentage of methacrylic acid and acrylic acid is 5%;

[0050] E-MAA-AA-3, the total mass percentage of methacrylic acid and acrylic acid is 9%;

[0051] In E-MAA-AA-4, the total mass percentage of methacrylic acid and acrylic acid is 1%.

[0052] b. Binary copolymers:

[0053] E-MAA, methacrylic acid content of 3% by mass;

[0054] E-AA, the mass percentage of acrylic acid is 3%.

[0055] 2. The glass fiber reinforced polypropylene materials of the embodiments and comparative examples of the present invention were prepared by the following preparation method:

[0056] The polypropylene resin, glass fiber, copolymer, stearate lubricant and antioxidant are mixed and added into a twin-screw extruder, and melt-extruded at 180-210° C. to obtain glass fiber reinforced polypropylene material.

[0057] 3. Performance testing

[0058] Tensile strength: dumbbell-shaped spline, tested according to GB / T 1040.1-2006, tensile rate 10mm / min.

[0059] Izod impact strength: tested in accordance with GB / T 1843-2008.

[0060] Plastic hot plate welding strength test: The prepared glass fiber reinforced polypropylene was injection molded at 230°C, medium speed and medium pressure to obtain 80mm*40mm*10mm specimens. After contact heating on a hot plate at 250°C for 1 minute, the injection-molded specimens were hot plate welded.

[0061] Examples 1 to 11 and Comparative Examples 1 to 6

[0062] The weight percentages of the components in the glass fiber reinforced polypropylene materials in Examples 1 to 11 and Comparative Examples 1 to 6 are shown in Table 1.

[0063] Table 1 Weight percentage of each component in the glass fiber reinforced polypropylene material in Examples 1 to 11 and Comparative Examples 1 to 6

[0064]

[0065] The performance test results of the glass fiber reinforced polypropylene materials in various embodiments and comparative examples according to the above-mentioned method are shown in Table 2.

[0066] Table 2 Test results of various embodiments and comparative examples

[0067]

[0068]

[0069] The tensile strength of the injection molded strips of the glass fiber reinforced polypropylene material of the present invention reaches 86-92 MPa, and the unnotched impact strength is greater than 68 kJ / m 2 , that is, to maintain good mechanical properties; the tensile strength of the welded strips reaches 27-31MPa, and the unnotched impact strength reaches 38-45kJ / m 2 , that is, it has excellent welding strength and no metal plates stick during the welding process.

[0070] It can be seen from Examples 1 to 3 that the type of polypropylene resin has a certain influence on the mechanical properties and welding strength of glass fiber reinforced polypropylene materials, among which homopolymer polypropylene and copolymer polypropylene are better than random copolymer polypropylene. It can be found from Examples 1, 4 to 5 and Comparative Example 1 that not all compatibilizers can significantly improve the welding performance while maintaining the mechanical properties of glass fiber reinforced polypropylene materials. When PP-g-MAH is used as a compatibilizer, it will not only reduce the mechanical properties and welding strength of glass fiber reinforced polypropylene materials, but also cause it to stick to the metal plate during welding. At the same time, combined with Figure 1 and Figure 2 It was also found that when E-MAA-AA was used as a compatibilizer, the resin matrix was evenly dispersed between the glass fibers and wrapped around them, thereby improving the mechanical properties and weld strength of the glass fiber-reinforced polypropylene material. However, when PP-g-MAH was used as a compatibilizer, the resin matrix had difficulty effectively wrapping the glass fibers, causing the glass fibers to separate from the resin matrix, resulting in a decrease in the mechanical properties and weld strength of the glass fiber-reinforced polypropylene material. Furthermore, it was found that the tensile strength and weld strength of the glass fiber-reinforced polypropylene material first increased and then decreased with increasing acrylic acid content in the copolymer (E-MAA-AA). This is mainly due to the fact that as the acrylic acid content in the copolymer increases, the compatibility between the glass fiber and the polypropylene resin increases, leading to increases in tensile strength and weld strength. However, as the acrylic acid content further increases, not only does it affect the strength of the polypropylene resin, causing a decrease in the tensile strength of the glass fiber-reinforced polypropylene material, but it also makes it difficult to separate the resin and glass fiber during the welding process, resulting in poor melt bonding and, in turn, a decrease in weld strength.

[0071] As shown in Examples 1, 6, Comparative Examples 2, and 3, when calcium stearate or ethylene bisstearamide is used as a lubricant, even when combined with ethylene-methacrylic acid-acrylic acid terpolymer (E-MAA-AA), it is difficult to achieve both good mechanical properties and weld strength in a glass fiber-reinforced polypropylene material. Furthermore, Comparative Examples 4 and 5 also show that either excessive or insufficient amounts of the copolymer added are detrimental to improving the mechanical properties and weld strength of the glass fiber-reinforced polypropylene material.

[0072] The above embodiments of the present invention are merely examples for the purpose of clearly illustrating the present invention and are not intended to limit the embodiments of the present invention. Those skilled in the art will appreciate that other variations or modifications may be made based on the above description. It is not necessary and impossible to enumerate all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention are intended to be included within the scope of protection of the claims of the present invention.

Claims

1. A glass fiber reinforced polypropylene material, characterized in that: Calculated by weight, it includes the following components: 60-80 parts of polypropylene resin, 20-40 parts of glass fiber, 0.3-3 parts of copolymer, and 0.2-2 parts of stearate lubricant; wherein the copolymer is one or more of ethylene-acrylic acid copolymer, ethylene-methacrylic acid copolymer, and ethylene-methacrylic acid-acrylic acid copolymer.

2. The glass fiber reinforced polypropylene material according to claim 1, characterized in that: The polypropylene resin has a melt index of 1 to 5 g / 10 min measured at 230° C. and 2.16 kg according to GB / T3682.2-2018 standard.

3. The glass fiber reinforced polypropylene material according to claim 2, characterized in that: The polypropylene resin is homopolymer polypropylene and / or block copolymer polypropylene.

4. The glass fiber reinforced polypropylene material according to claim 1, characterized in that: The mass percentage of acrylic acid in the ethylene-acrylic acid copolymer is ≥1%; Or the mass percentage of methacrylic acid in the ethylene-methacrylic acid copolymer is ≥1%; Or the total mass percentage of acrylic acid and methacrylic acid in the ethylene-methacrylic acid-acrylic acid copolymer is ≥1%.

5. The glass fiber reinforced polypropylene material according to claim 4, characterized in that: The total mass percentage of acrylic acid and methacrylic acid in the ethylene-methacrylic acid-acrylic acid copolymer is 1% to 9%.

6. The glass fiber reinforced polypropylene material according to claim 1, characterized in that: The stearate lubricant is at least one of pentaerythritol stearate, ethylene glycol stearate, glyceryl stearate or butyl stearate.

7. The glass fiber reinforced polypropylene material according to claim 1, characterized in that: The invention also includes 0.01 to 5 parts by weight of an antioxidant.

8. The glass fiber reinforced polypropylene material according to claim 7, characterized in that: The antioxidant is one or more of phenol antioxidants, phosphite antioxidants, divalent sulfur antioxidants and hindered amine antioxidants.

9. A method for preparing the glass fiber reinforced polypropylene material according to any one of claims 1 to 8, characterized in that: The following steps are involved: The components are mixed and melt-extruded to obtain glass fiber reinforced polypropylene material.

10. Use of the glass fiber reinforced polypropylene material according to any one of claims 1 to 8 in automobile interior and exterior trims, household appliances or electronic appliances.

Images