A polypropylene material with easy demoulding and good appearance and its preparation method and application

Abstract

The present invention relates to a polypropylene material with good appearance and easy demoulding, and a preparation method and application thereof, the components of which include polypropylene, silica gel, glass fiber, compatibilizer, antioxidant, and cyclic organic siloxane. The glass fiber reinforced polypropylene composite material with easy demoulding has good demoulding performance and anti-blooming performance.

Description

Technical Field

[0001] The invention belongs to the field of modified plastics, and particularly relates to a polypropylene material with easy demoulding and good appearance, and a preparation method and application thereof. Background Art

[0002] General plastic engineering is one of the important development directions of modified plastics. As the most common general plastic variety, polypropylene is widely used in the automotive industry due to its low density. Glass fiber reinforced polypropylene is the most common polypropylene engineering method, but for large plastic products, glass fiber reinforced polypropylene has the disadvantage of being difficult to demold, which limits its application.

[0003] Technically, a certain amount of silicone is often added to achieve lubrication. However, silicone has a high molecular weight and is not easy to disperse in the material. It is easy to cause flowery problems on the appearance of injection molded parts, affecting the use of the material. Summary of the invention

[0004] In view of the defects of the prior art, the technical problem to be solved by the present invention is to provide a polypropylene material which is easy to demould and has a good appearance, and a preparation method and application thereof.

[0005] A polypropylene material of the present invention comprises, by weight:

[0006]

[0007] The number average molecular weight of polypropylene is 20,000-110,000; the number average molecular weight of silicone is 400,000-800,000.

[0008] Number average molecular weight test method: GPC (condensation permeation chromatography) method.

[0009] Polypropylene is the resin matrix, and silicone has a certain molecular weight. If the molecular weight of polypropylene is too large or too small, silicone is difficult to disperse well in the resin. If the molecular weight of silicone is high, the viscosity is greater, and it is difficult to disperse and disentangle; if the molecular weight is too small, the lubrication effect is limited and the demoulding effect is poor.

[0010] Preferably, the number average molecular weight of the polypropylene is 30,000-60,000.

[0011] Preferably, the number average molecular weight of the silicone is 600,000-700,000.

[0012] Preferably, the compatibilizer is a polymer grafted with polypropylene and an unsaturated acid or anhydride, such as maleic anhydride grafted polypropylene and glycidyl methacrylate grafted polypropylene.

[0013] Preferably, the antioxidant is one or more of organic phosphites, alkylated monophenols or polyphenols, alkylation reaction products of polyphenols and dienes, butylation reaction products of p-cresol or dicyclopentadiene, alkylated hydroquinones, hydroxylated thiodiphenyl ethers, alkylene-bisphenols, benzyl compounds, and polyol ester antioxidants.

[0014] Preferably, the cyclic organosiloxane is octamethylcyclotetrasiloxane D4, hexamethylcyclotrisiloxane D3, hexaphenylcyclotrisiloxane D3 2P , Tetramethylcyclotetrasiloxane D4 H One or more of the .

[0015] Further preferably, the cyclic organosiloxane is octamethylcyclotetrasiloxane D4, hexamethylcyclotrisiloxane D3, hexaphenylcyclotrisiloxane D3 2P , Tetramethylcyclotetrasiloxane D4 H At least two of the .

[0016] Furthermore, the mass ratio of octamethylcyclotetrasiloxane to hexamethylcyclotrisiloxane is (0.2:0.8) to (0.8:0.2). The silicone is added in the form of silicone masterbatch, the matrix is ​​polypropylene, wherein the mass percentage of silicone in the silicone masterbatch is 50-60%, and the matrix polypropylene and the polypropylene with a number average molecular weight of 20,000-110,000 can be the same or different.

[0017] Preferably, by weight, the components include:

[0018]

[0019] A method for preparing the polypropylene material of the present invention comprises:

[0020] Weigh each component according to weight ratio, feed the glass fiber side, and add the premix of other raw material components into a twin-screw extruder for melting, mixing and dispersion, and then extrude and granulate to obtain a polypropylene material with good appearance and easy demoulding.

[0021] The extrusion temperature is 170-250°C.

[0022] The polypropylene material of the present invention is used in automobile plastic parts, such as automobile auxiliary instrument panel, pillars, seats and other parts.

[0023] Beneficial Effects

[0024] The present invention provides an easy-to-release glass fiber reinforced polypropylene composite material and a preparation method thereof, which can significantly improve the demoulding property of the material. In the technical solution adopted by the present invention, the polypropylene resin and silicone masterbatch of specific molecular weight, the synergistic effect of the two improves the demoulding property of the material. In addition, in view of the problem that the silicone masterbatch is prone to blooming on the surface of the material, the solvation technology of small molecular weight cyclic organic siloxane is adopted. During the processing, the cyclic organic siloxane is in a liquid state, and the silicone in the silicone masterbatch can be solvated to achieve the disentanglement of the silicone molecular chain. Since silicone has a certain molecular weight distribution, the use of compounded cyclic organic siloxane can more effectively achieve the effective disentanglement of silicones of different molecular weights, thereby achieving good dispersion of the silicone masterbatch in the material and solving the blooming problem.

[0025] The easy-to-release glass fiber reinforced polypropylene composite material of the invention has good demoulding performance and anti-blooming performance. DETAILED DESCRIPTION

[0026] The present invention will be further described below in conjunction with specific embodiments. It should be understood that these embodiments are only intended to illustrate the present invention and are not intended to limit the scope of the present invention. In addition, it should be understood that after reading the content taught by the present invention, those skilled in the art may make various changes or modifications to the present invention, and these equivalent forms fall within the scope limited by the appended claims of the application equally.

[0027] 1. Source of raw materials

[0028] Polypropylene-1: polypropylene, model Z30S, purchased from Sino-Korea Petrochemical, number average molecular weight 30,000;

[0029] Polypropylene-2: polypropylene, model T30S, purchased from Zhenhai Petrochemical, number average molecular weight 60,000;

[0030] Polypropylene-3: Polypropylene, model B1101, purchased from Yanshan Petrochemical, number average molecular weight 110,000;

[0031] Polypropylene-4: polypropylene, model H9018, purchased from Lanzhou Petrochemical, number average molecular weight 25,000;

[0032] Polypropylene-5: polypropylene, model BI997, purchased from ExxonMobil, number average molecular weight of 10,000;

[0033] Polypropylene-6: polypropylene, model K9010, purchased from Formosa Chemical Corporation, number average molecular weight 150,000;

[0034] Silicone masterbatch 1: AS-025, PP matrix, silicone number average molecular weight 600,000, effective content 50%, provided by Shanghai Fengcai Company;

[0035] Silicone masterbatch 2: AS-025D, PP matrix, silicone number average molecular weight 800,000, effective content 50%, provided by Shanghai Fengcai Company;

[0036] Silicone masterbatch 3: AS-025E, PP matrix, silicone number average molecular weight 400,000, effective content 50%, provided by Shanghai Fengcai Company;

[0037] Silicone masterbatch 4: AS-025F, PP matrix, silicone number average molecular weight 900,000, effective content 50%, provided by Shanghai Fengcai Company;

[0038] Silicone masterbatch 5AS-025G, PP matrix, silicone number average molecular weight 300,000, effective content 50%, provided by Shanghai Fengcai Company;

[0039] Glass fiber: Model ECS13-04-508A, Taishan Fiberglass;

[0040] Compatibilizer: maleic anhydride grafted polypropylene, model CA100, purchased from Arkema;

[0041] Antioxidant: Antioxidant 1010, purchased from BASF;

[0042] Cyclic organosiloxane 1: octamethylcyclotetrasiloxane D4, provided by Dow Corning;

[0043] Cyclic organosiloxane 2: hexamethylcyclotrisiloxane D3, provided by Dow Corning;

[0044] Siloxane: γ-aminopropyltriethoxysilane KH550, provided by Shin-Etsu Co., Ltd., Japan.

[0045] 2. Preparation methods of embodiments and comparative examples

[0046] (1) putting polypropylene, silicone masterbatch, compatibilizer, antioxidant and silane agent into a high-speed mixer and mixing at a speed of 400 r / min for 5 min to obtain a premix;

[0047] (2) adding the premix into a twin-screw extruder, feeding glass fiber at the side, performing melt mixing and dispersion, extruding granulation, and drying at below 80° C. to obtain a polypropylene composite material; wherein the processing temperature of each section of the twin-screw extruder is: 170° C. for zone 1, 190° C. for zone 2, 230° C. for zone 3, 230° C. for zone 4, 235° C. for zone 5, 235° C. for zone 6, 240° C. for zone 7, 240° C. for zone 8, and 230° C. for zone 9; and the screw speed of the twin-screw extruder is 500 r / min.

[0048] 3. Test standards and methods Tensile strength: Test standard ISO 527-2-2012, sample size 150×10×4mm, tensile speed 50mm / min; demolding force test is carried out on a mold with a pressure sensor, and the demolding force value is recorded. The larger the value, the worse the demolding property and the more difficult it is to demold.

[0049] The material appearance can be injection molded into a 100mm*100mm*3mm square plate, photographed, and then the area of ​​surface floweriness can be calculated using image processing software.

[0050] Table 1 Proportions (parts by weight) and performance effects of the embodiments

[0051]

[0052] Table 2 shows the proportions (parts by weight) and performance effects of the embodiments

[0053]

[0054] Table 3 Comparative Examples (parts by weight) and performance effects

[0055]

[0056] As can be seen from Table 1, the demoulding properties and surface blooming of Examples 8-10 using compound cyclic silane and silicone masterbatch are the best, while the surface blooming effect of Examples 1-7 using single cyclic silane is slightly poor. Table 2 Performance effect of the proportions (weight parts) of the examples. As can be seen from Examples 12-15 in Table 2, within the limited range of silicone masterbatch molecular weight, glass fiber content, and cyclic silane content, the demoulding properties and surface blooming of the materials are good.

[0057] As can be seen from Table 3, the molecular weight of the polypropylene resin selected in Comparative Examples 1 and 2 is not within the restricted range, the final demoulding force is large, and the surface blooming is also poor. The molecular weight of the silicone in the silicone particles selected in Comparative Examples 3 and 4 is not within the restricted range, and a similar situation occurs. Comparative Example 5 uses polypropylene resin and silicone masterbatch within the restricted range, but the small molecule silane selects common siloxane instead of cyclic organosiloxane. Although the demoulding force is reduced, the surface blooming problem is not solved in the end. Comparative Example 6 does not use silicone masterbatch, and the demoulding property is the worst. Comparative Example 7 does not use any small molecule silane, the material appearance is poor, and the surface blooming area is the largest.

Claims

1. A polypropylene material, characterized in that: By weight, the components include: Polypropylene 36.25-95 parts; Silicone 0.25-2.5 parts; Glass fiber 5-50 parts; Compatibilizer 0.5-5 parts; Antioxidant 0.2-2 parts; 0.2-2 parts of cyclic organosiloxane; The number average molecular weight of polypropylene is 20,000-110,000; the number average molecular weight of silicone is 400,000-800,000, and the number average molecular weight is tested by GPC gel permeation chromatography; The silicone is added in the form of silicone masterbatch, in which the matrix is ​​polypropylene, and the mass percentage of silicone in the silicone masterbatch is 50-60%.

2. The polypropylene material according to claim 1, characterized in that: The number average molecular weight of the polypropylene is 30,000-60,000.

3. The polypropylene material according to claim 1, characterized in that: The number average molecular weight of the silicone is 600,000-700,000.

4. The polypropylene material according to claim 1, characterized in that: The compatibilizer is a polymer grafted with polypropylene and unsaturated acid or anhydride; The antioxidant is one or more of organic phosphites, alkylated monophenols or polyphenols, alkylation reaction products of polyphenols and dienes, butylation reaction products of p-cresol or dicyclopentadiene, alkylated hydroquinones, hydroxylated thiodiphenyl ethers, alkylene-bisphenols, benzyl compounds, and polyol ester antioxidants.

5. The polypropylene material according to claim 1, characterized in that: The cyclic organic siloxane is one or more of octamethylcyclotetrasiloxane, hexamethylcyclotrisiloxane, hexaphenylcyclotrisiloxane and tetramethylcyclotetrasiloxane.

6. The polypropylene material according to claim 5, characterized in that: The mass ratio of the octamethylcyclotetrasiloxane to the hexamethylcyclotrisiloxane is (0.2:0.8) to (0.8:0.2).

7. The polypropylene material according to claim 1, characterized in that: By weight, the components include: Polypropylene 55-75 parts; Silicone 0.5-1.5 parts; 30-40 parts of glass fiber; 2-4 parts of compatibilizer; Antioxidant 0.4-1 part; Cyclic organosiloxane 0.8-1.5 parts.

8. A method for preparing the polypropylene material according to claim 1, comprising: Weigh each component according to weight ratio, feed the glass fiber side, and add the premix of other raw material components into a twin-screw extruder for melting, mixing and dispersion, and then extrude and granulate to obtain a polypropylene material with good appearance and easy demoulding.

9. Use of the polypropylene material according to claim 1 in automobile plastic parts.

Images