Bright white polyphenylene sulfide composite material and preparation method thereof

Abstract

The invention discloses a bright white polyphenylene sulfide composite material and a preparation method thereof, the bright white polyphenylene sulfide composite material comprises the following raw material components in parts by mass: 30-50 parts of polyphenylene sulfide, 30-45 parts of glass fiber, 0.5-4 parts of a color modifier, 0.2-0.8 part of a coupling agent, and 0.5-1.5 parts of a lubricant, the color modifier is selected from a copolymer containing two or more of the following functional groups: an epoxy group, an amino group, a carboxyl group, a hydroxyl group, an isocyanate group, an acylamino group, an acetamido group, a sulfonic acid group, a sulfonamide group, a silanol group, an alkoxy group, a silane group, an aldehyde group, an acetyl group and an anhydride group. According to the invention, the white degree and gloss degree of the polyphenylene sulfide composite material can be obviously improved under the condition that a large amount of inorganic filler is not added, and the bright white composite material is obtained.

Description

Technical Field

[0001] The invention relates to the technical field of polyphenylene sulfide materials, in particular to the technical field of bright white polyphenylene sulfide composite materials. Background Art

[0002] Polyphenylene sulfide is a new type of high-performance thermoplastic resin polymerized from p-dichlorobenzene. The benzene ring structure in the main chain of polyphenylene sulfide molecules gives the polymer rigidity and strength, while the sulfide bond makes the polymer show a certain degree of flexibility. Therefore, polyphenylene sulfide has excellent heat resistance, flame retardancy, insulation, corrosion resistance, dimensional stability, etc. At the same time, as one of the six major special engineering plastics and eight major aerospace materials, it has been widely used in the fields of electronics, machinery, aerospace, automobiles, new energy, food and chemical industry.

[0003] With the increasing demand for polyphenylene sulfide and the continuous expansion of its application fields, some fields (aerospace, automobiles, etc.) have higher and higher requirements for polyphenylene sulfide products. The application scenarios in these fields require the selected materials to have high mechanical properties, thermal stability, weather resistance and dimensional stability. Some special plates such as automobile engine cylinder head covers require high temperature resistance and corrosion resistance during use. Polyphenylene sulfide has obvious advantages in strength, thermal stability, dimensional stability, etc., making it the preferred material for replacing steel with plastic in the fields of automobiles and aerospace. However, polyphenylene sulfide turns yellow after high-temperature processing and has poor color stability. Therefore, the prepared modified PPS composite material of natural color is unsatisfactory in appearance, which is not conducive to its practical application. In the prior art, in order to solve this problem, whitening agents or some high-whiteness substances are usually added during the processing process to improve the whiteness of the composite material.

[0004] For example, Chinese invention patent CN108034249A discloses a high-whiteness polyphenylene sulfide alloy and a preparation method thereof, which improves the whiteness of the PPS alloy and reduces the color difference value during processing by using heterogeneous resins and white inorganic mineral powders. However, the large amount of inorganic fillers added will reduce the tensile strength, bending strength and other properties of the PPS composite material, which limits its practical application to a certain extent. Summary of the invention

[0005] In view of the problems that polyphenylene sulfide materials have poor thermal stability, are easy to change color, and the addition of a large amount of whitening agent or high-whiteness filler will lead to a decrease in their performance, the present invention proposes a new bright white polyphenylene sulfide composite material and a preparation method thereof that can solve the above technical problems.

[0006] The technical solution of the present invention is as follows:

[0007] A bright white polyphenylene sulfide composite material, characterized in that it comprises the following raw material components in parts by mass: 30-50 parts of polyphenylene sulfide, 30-45 parts of glass fiber, 0.5-4 parts of color modifier, 0.2-0.8 parts of coupling agent, and 0.5-1.5 parts of lubricant, wherein the color modifier is selected from copolymers containing two or more of the following functional groups: epoxy group, amino group, carboxyl group, hydroxyl group, isocyanate group, amide group, acetamide group, sulfonic acid group, sulfonamide group, silanol group, alkoxy group, silane group, aldehyde group, acetyl group, and anhydride group.

[0008] The above technical scheme of the present invention fully considers the reasons for the color change of polyphenylene sulfide, including thermal degradation during the melt blending process. During the degradation, due to the weak CS bond energy, it will first break the chain and decompose to produce sulfur radicals and benzene radicals. The molecular chain structure containing these radicals will undergo a cross-linking reaction under the action of oxygen to generate color-changing groups containing benzene and sulfur, resulting in a color change of the material. The above problems are overcome by the introduction of a color modifier. The active functional groups in the color modifier have good reactivity with sulfur radicals and benzene radicals, significantly inhibiting the occurrence of color change reactions. The whiteness and glossiness of the composite material can be significantly improved without adding a large amount of inorganic fillers, thereby obtaining a bright white composite material.

[0009] According to some preferred embodiments of the present invention, the color modifier is selected from Contains the first ingredient and the second ingredient and a third component, wherein the first component is an olefin, the second component is an acrylate, and the third component is The third component is glycidyl acrylate and / or maleic anhydride .

[0010] According to some preferred embodiments of the present invention, the color modifier is selected from one or more of ethylene-butyl acrylate-glycidyl methacrylate ternary random copolymer such as Arkema AX8700, ethylene-methyl acrylate-glycidyl methacrylate ternary random copolymer such as Arkema AX8900 and ethylene-methacrylate grafted maleic anhydride copolymer.

[0011] The inventors unexpectedly discovered that the color modifier in the above preferred embodiment has excellent thermal stability during processing, a wide melting temperature window, and a structure containing a large number of highly reactive functional groups such as epoxy functional groups that can react with free radicals generated by thermal decomposition of PPS. It can significantly inhibit color changes in the product and further improve the whiteness of the melt-extruded product.

[0012] According to some preferred embodiments of the present invention, the coupling agent is selected from silane coupling agents such as KH-560, KH-570, and KH-792, the lubricant is selected from lipid organic substances such as siloxanes and silicone powder, fatty acid amide organic substances such as stearic acid amide, erucic acid amide, ricinoleamide, N,N'-ethylenebisstearamide, N,N'-ethylenebisricinoleamide, fatty alcohol organic substances such as stearyl alcohol, pentaerythritol and hydrocarbon organic substances such as paraffin and polyethylene wax, and the glass fiber is selected from alkali-free continuous glass fiber.

[0013] According to some preferred embodiments of the present invention, the lubricant is selected from silicone powder with a siloxane content of 25-30%.

[0014] The silicone powder is a commercial product, which is composed of siloxane, silicon dioxide and additives.

[0015] The lubricant selected in this preferred embodiment has good dispersibility and low viscosity, can better disperse the color modifier and bring it into the polyphenylene sulfide resin matrix, and can also reduce the viscosity of the resin and reduce the heat generated by friction and shear during the blending process, thereby further reducing the cross-linked chromophore groups generated by the polyphenylene sulfide resin during the processing.

[0016] According to some preferred embodiments of the present invention, the polyphenylene sulfide is selected from polyphenylene sulfide having a melt index of 300-450 g / 10 min at 316° C. and 5 kg, and / or a number average molecular weight of 10,000-80,000.

[0017] More preferably, the polyphenylene sulfide is selected from polyphenylene sulfide having a melt index of 300-450 g / 10 min at 316° C. and 5 kg, and a number average molecular weight of 40,000-50,000 with excellent comprehensive properties such as processability and mechanical properties.

[0018] The present invention further provides a method for preparing the bright white polyphenylene sulfide composite material, which comprises: mixing the raw material components and then extruding and granulating them.

[0019] According to some preferred embodiments of the present invention, the preparation method comprises:

[0020] The polyphenylene sulfide, color modifier, coupling agent and lubricant are mixed at high speed to obtain a mixture after mixing evenly;

[0021] The mixed material is added into a co-rotating twin-screw extruder for melt extrusion granulation, the glass fiber is added during the melt extrusion process, and then the obtained granules are screened and dried to obtain the bright white polyphenylene sulfide composite material; wherein the screw length-to-diameter ratio of the co-rotating twin-screw extruder is 35-40:1, and the melt extrusion temperature is 220-310°C.

[0022] According to some preferred embodiments of the present invention, the co-rotating twin-screw extruder has ten temperature control zones in sequence, and the temperature controls are: zone one 220-230°C, zone two 250-260°C, zone three 280-290°C, zone four 300-310°C, zone five 300-310°C, zone six 280-290°C, zone seven 280-290°C, zone eight 270-280°C, zone nine 270-280°C, zone ten 230-240°C, and the glass fiber is added in zone five.

[0023] The present invention has the following beneficial effects:

[0024] (1) The present invention adds a color modifier to the polyphenylene sulfide resin. Through the reaction between the active functional groups of the color modifier and the free radicals generated by the thermal decomposition of polyphenylene sulfide, the cross-linking reaction between the free radicals and the chromophores generated by the cross-linking reaction are inhibited, thereby improving the yellowing phenomenon of polyphenylene sulfide after high-temperature extrusion;

[0025] (2) In some preferred embodiments, silicone powder is added to the preparation method of the present invention, which can make the color modifier more evenly distributed in the polyphenylene sulfide resin system, and can promote the color modifier to fully exert its efficacy. At the same time, the addition of silicone powder can reduce the viscosity of the resin, reduce the heat generated by friction shear during the blending process, and further reduce the chromophore groups generated by the heat cross-linking of the polyphenylene sulfide resin during the processing;

[0026] (3) The invention has a simple formula, easy-to-control process, low equipment requirements, relatively low cost, and is easy to mass-produce. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 Comparative images of the injection-molded strips of composite material pelletized particles obtained in Example 1, Example 2 and Comparative Example 1. DETAILED DESCRIPTION

[0028] The present invention is further described in detail below through specific embodiments, but this should not be construed as limiting the scope of the present invention to the following examples. Without departing from the above-mentioned method concept of the present invention, various substitutions or changes made according to common technical knowledge and conventional means in the art should be included in the scope of the present invention.

[0029] Example 1

[0030] Bright white polyphenylene sulfide (PPS) composites were prepared by the following steps:

[0031] (1) Pre-dispersing 57 parts of polyphenylene sulfide having a melt index of 320 g / 10 min (316° C., 5 kg) and a number average molecular weight of 50,000, 0.5 parts of silicone powder having a siloxane content of 25%, 2 parts of ethylene-butyl acrylate-glycidyl methacrylate terpolymer (Arkema AX8700) and 0.5 parts of silane coupling agent KH-560 in a mixer at high speed for 10 min to obtain a mixed material;

[0032] (2) The mixed material is added into a co-rotating twin-screw extruder for melt extrusion and granulation. The length-diameter ratio of the screw of the co-rotating twin-screw extruder is 40:1. The extruder has ten temperature control zones, and the temperature control of each zone is: 230°C for zone 1, 250°C for zone 2, 280°C for zone 3, 300°C for zone 4, 310°C for zone 5, 290°C for zone 6, 280°C for zone 7, 270°C for zone 8, 270°C for zone 9, and 240°C for zone 10. Alkali-free continuous glass fiber (model EW723AK-2000) is added into the feeding port on the side of zone 5. By controlling the feeding amount and speed of the main machine, the feeding amount of the glass fiber is ensured to reach 40 parts by weight. The composite material is dispersed by screw shearing, melt extrusion, water-cooled strand cutting, screening, drying, and packaging to obtain a bright white polyphenylene sulfide composite material.

[0033] Example 2

[0034] Bright white polyphenylene sulfide (PPS) composites were prepared by the following steps:

[0035] (1) Pre-dispersing 54 parts of polyphenylene sulfide having a melt index of 320 g / 10 min (316° C., 5 kg) and a number average molecular weight of 50,000, 0.5 parts of silicone powder having a siloxane content of 25%, 5 parts of ethylene-methyl acrylate-glycidyl methacrylate terpolymer (Arkema AX8900) and 0.5 parts of silane coupling agent KH-560 in a mixer at high speed for 10 min to obtain a mixed material;

[0036] (2) The mixed material is added into a co-rotating twin-screw extruder for melt extrusion and granulation. The length-diameter ratio of the screw of the co-rotating twin-screw extruder is 40:1. The extruder has ten temperature control zones, and the temperature control of each zone is: 230°C for zone 1, 250°C for zone 2, 280°C for zone 3, 300°C for zone 4, 310°C for zone 5, 290°C for zone 6, 280°C for zone 7, 270°C for zone 8, 270°C for zone 9, and 240°C for zone 10. Alkali-free continuous glass fiber (model EW723AK-2000) is added into the feeding port on the side of zone 5. By controlling the feeding amount and speed of the main machine, the feeding amount of the glass fiber is ensured to reach 40 parts by weight. The composite material is dispersed by screw shearing, melt extrusion, water-cooled strand cutting, screening, drying, and packaging to obtain a bright white polyphenylene sulfide composite material.

[0037] Example 3

[0038] Bright white polyphenylene sulfide (PPS) composites were prepared by the following steps:

[0039] (1) Pre-dispersing 54 parts of polyphenylene sulfide having a melt index of 320 g / 10 min (316° C., 5 kg) and a number average molecular weight of 50,000, 0.5 parts of pentaerythritol stearate, 5 parts of ethylene-methacrylate grafted maleic anhydride, and 0.5 parts of silane coupling agent KH-560 in a mixer at high speed for 10 min to obtain a mixed material;

[0040] (2) The mixed material is added into a co-rotating twin-screw extruder for melt extrusion and granulation. The length-diameter ratio of the screw of the co-rotating twin-screw extruder is 40:1. The extruder has ten temperature control zones, and the temperature control of each zone is: 230°C for zone 1, 250°C for zone 2, 280°C for zone 3, 300°C for zone 4, 310°C for zone 5, 290°C for zone 6, 280°C for zone 7, 270°C for zone 8, 270°C for zone 9, and 240°C for zone 10. Alkali-free continuous glass fiber (model EW723AK-2000) is added into the feeding port on the side of zone 5. By controlling the feeding amount and speed of the main machine, the feeding amount of the glass fiber is ensured to reach 40 parts by weight. The composite material is dispersed by screw shearing, melt extrusion, water-cooled strand cutting, screening, drying, and packaging to obtain a bright white polyphenylene sulfide composite material.

[0041] Comparative Example 1

[0042] The polyphenylene sulfide (PPS) composite material was prepared by the following steps:

[0043] (1) Pre-dispersing 59.5 parts of polyphenylene sulfide having a melt index of 320 g / 10 min (316° C., 5 kg) and a number average molecular weight of 50,000 and 0.5 parts of silane coupling agent KH-560 in a mixer at high speed for 10 min to obtain a mixed material;

[0044] (2) adding the mixed material into a co-rotating twin-screw extruder for melt extrusion and granulation, wherein the co-rotating twin-screw extruder has a screw length-diameter ratio of 40:1; and contains ten temperature control zones, each of which has a temperature control of: 230°C for zone 1, 250°C for zone 2, 280°C for zone 3, 300°C for zone 4, 310°C for zone 5, 290°C for zone 6, 280°C for zone 7, 270°C for zone 8, 270°C for zone 9, and 240°C for zone 10; adding alkali-free continuous glass fiber (model EW723AK-2000) into the feeding port on the side of zone 5; ensuring that the feeding amount of the glass fiber reaches 40 parts by weight by controlling the feeding amount and the speed of the main machine; and obtaining a polyphenylene sulfide composite material by screw shearing dispersion, melt extrusion, water-cooled strand cutting, screening, drying, and packaging.

[0045] The pellets of the polyphenylene sulfide composite materials obtained in Examples 1-3 and Comparative Example 1 were injection molded under the same conditions, and the obtained injection molded strips were compared in color. It was found that the strips of Examples 1-3 were obviously whiter than the strips of the comparative example. The comparison diagram of the strips of Examples 1, 2 and Comparative Example 1 is shown in the attached figure. Figure 1 shown.

[0046] The above embodiments are only preferred implementations of the present invention, and the protection scope of the present invention is not limited to the above embodiments. All technical solutions under the concept of the present invention belong to the protection scope of the present invention. It should be pointed out that for ordinary technicians in this technical field, improvements and modifications without departing from the principle of the present invention should also be regarded as the protection scope of the present invention.

Claims

1. A bright white polyphenylene sulfide composite material, characterized in that: The invention comprises the following raw material components in parts by weight: 30-50 parts of polyphenylene sulfide, 30-45 parts of glass fiber, 0.5-4 parts of color modifier, 0.2-0.8 parts of coupling agent and 0.5-1.5 parts of lubricant, wherein the color modifier is selected from copolymers containing two or more of the following functional groups: epoxy group, amino group, carboxyl group, hydroxyl group, isocyanate group, amide group, acetamide group, sulfonic acid group, sulfonamide group, silanol group, alkoxy group, silane group, aldehyde group, acetyl group and anhydride group.

2. The bright white polyphenylene sulfide composite material according to claim 1, characterized in that: The color modifier is selected from a multi-component copolymer containing a first component, a second component and a third component, wherein the first component is an olefin, the second component is an acrylate, and the third component is glycidyl acrylate and / or maleic anhydride.

3. The bright white polyphenylene sulfide composite material according to claim 1, characterized in that: The color modifier is selected from one or more of ethylene-butyl acrylate-glycidyl methacrylate terpolymer, ethylene-methyl acrylate-glycidyl methacrylate terpolymer and ethylene-methacrylate grafted maleic anhydride copolymer.

4. The bright white polyphenylene sulfide composite material according to claim 1, characterized in that: The coupling agent is selected from silane coupling agent, the lubricant is selected from one or more of lipid organic matter, fatty acid amide organic matter, fatty alcohol organic matter and hydrocarbon organic matter, and the glass fiber is selected from alkali-free continuous glass fiber.

5. The bright white polyphenylene sulfide composite material according to claim 4, characterized in that: The lubricant is selected from silicone powder with a silicone content of 25-30%.

6. The bright white polyphenylene sulfide composite material according to claim 1, characterized in that: The polyphenylene sulfide is selected from polyphenylene sulfide having a melt index of 300-450 g / 10 min at 316° C. and 5 kg, and / or a number average molecular weight of 10,000-80,000.

7. The bright white polyphenylene sulfide composite material according to claim 6, characterized in that: The number average molecular weight of the polyphenylene sulfide is 40,000-50,000.

8. The method for preparing the bright white polyphenylene sulfide composite material according to any one of claims 1 to 7, characterized in that: It includes: The raw material components are mixed and then extruded into granules.

9. The preparation method according to claim 8, characterized in that: It includes: (1) mixing the polyphenylene sulfide, color modifier, coupling agent and lubricant at a high speed to obtain a mixture after mixing evenly; (2) adding the mixed material into a co-rotating twin-screw extruder for melt extrusion granulation, adding the glass fiber during the melt extrusion process, and then screening and drying the obtained granules to obtain the bright white polyphenylene sulfide composite material; wherein the screw length-to-diameter ratio of the co-rotating twin-screw extruder is 35-40:1, and the melt extrusion temperature is 220-310°C.

10. The preparation method according to claim 9, characterized in that: The co-rotating twin-screw extruder has ten temperature control zones in sequence, and the temperature controls are: zone one 220-230°C, zone two 250-260°C, zone three 280-290°C, zone four 300-310°C, zone five 300-310°C, zone six 280-290°C, zone seven 280-290°C, zone eight 270-280°C, zone nine 270-280°C, zone ten 230-240°C, and the glass fiber is added in zone five.

Images