WO2021012558A1 - Chiral silicon dioxide fiber-reinforced foamed polypropylene composite material - Google Patents

Abstract

The present invention relates to a chiral silicon dioxide fiber-reinforced foamed polypropylene composite material, comprising the following components: a polypropylene resin, talcum powder, a chiral silicon dioxide fiber, a surfactant solution, a micro-pore foaming agent, a phase-change material microcapsule, and an aid, wherein the surfactant solution is a linear sodium alkyl benzene sulfonate aqueous solution. The present invention uses the chiral silicon dioxide fiber to improve the mechanical properties of the material; the chiral silicon dioxide fiber has chiral induction under the action of hydrogen bonds among molecules, orientation of polypropylene molecular chain fragments can be reduced, the polypropylene molecular chain fragments can be regularly arranged, and thus the mechanical properties of a polypropylene injection molding finished product can be improved; moreover, due to a chiral spiral structure of the chiral silicon dioxide fiber, and by means of chiral spiral induction on polypropylene, winding of molecular chains can be intensified, and the mechanical properties of the polypropylene injection molding finished product can be further improved; and compared with an ordinary silicon dioxide fiber, the chiral silicon dioxide fiber can more effectively improve the mechanical properties of a polypropylene material and an injection molding part thereof.

Description

Chiral silica fiber reinforced foamed polypropylene composite material Technical field

The invention relates to the field of polypropylene materials, in particular to a chiral silica fiber reinforced foamed polypropylene composite material.

Background technique

In recent years, polypropylene foam injection molding technology has attracted more and more attention. This technology refers to the use of polypropylene material as the matrix, through the injection process, under the action of gas internal pressure, the middle layer of the product is densely packed with closed micropores with sizes ranging from ten to tens of microns, and both sides have a dense skin structure; thus To achieve the purpose of saving materials and reducing weight. The technology can be divided into physical method and chemical method; the chemical method refers to adding a certain amount of foaming agent to polypropylene. After injection molding, the part material expands under the action of the foaming agent to form an intermediate layer. Closed pores ranging from tens of microns. This micro-foam injection molding technology breaks through many limitations of traditional injection molding and can more fully realize weight reduction, high efficiency, and low cost production. However, the mechanical properties of foamed polypropylene injection molded products are often not high and need to be reinforced; fiber (such as glass fiber, carbon fiber, silica fiber) reinforcement materials are usually added to improve its mechanical properties, but the reinforcement effect remains to be Further improve.

Summary of the invention

The invention overcomes the shortcomings of the prior art and provides a foamed polypropylene composite material with good reinforcement effect.

In order to achieve the above-mentioned objective, the technical solution adopted by the present invention is:

One aspect of the present invention provides a chiral silica fiber reinforced foamed polypropylene composite material, which comprises the following components: polypropylene resin, talc, chiral silica fiber, surfactant solution, and microcellular foaming agent , Phase change material microcapsules and additives; the surfactant solution is an aqueous solution of sodium linear alkylbenzene sulfonate.

As a preferred solution, the auxiliary agent includes a primary antioxidant and a secondary antioxidant.

As a more preferred solution, it includes the following composition: polypropylene resin 60-70wt%, talc 9-16wt%, chiral silica fiber 8-15wt%, surfactant solution 3-8wt%, microcellular foaming 2-4wt% of the phase change material, 1.5-3wt% of the phase change material microcapsule, 0.5-1wt% of the main antioxidant, and 0.25-1wt% of the auxiliary antioxidant.

As a preferred solution, the chiral silica fiber has a length of 3.0-8.0 μm and a diameter of 50-80 nm;

As a preferred solution, the microcellular foaming agent is a mixture of sodium bicarbonate and citric acid.

As a more preferred solution, the mass ratio of sodium bicarbonate to citric acid is 5:7.

As a preferred solution, the phase change material is an intermediate temperature phase change material, and the phase change temperature is 90-130°C.

As a preferred solution, the phase change material is xylitol microcapsules and/or meso-erythritol microcapsules.

As a preferred solution, the concentration of the linear sodium alkylbenzene sulfonate aqueous solution is 70-80 wt%.

Another aspect of the present invention provides a preparation method of the chiral silica fiber reinforced foamed polypropylene composite material, which is obtained by uniformly mixing the raw materials according to the ratio.

The third aspect of the present invention provides a foamed polypropylene product, which is prepared by mixing the above chiral silica fiber reinforced foamed polypropylene composite material, or the mixture prepared by the above preparation method, and performing injection molding foam molding. .

The beneficial technical effect of the present invention is to provide a foamed polypropylene composite material with good reinforcement effect. The present invention uses chiral silica fiber to improve the mechanical properties of the material; under the action of the surfactant aqueous solution, the chiral silica fiber produces chirality induction through intermolecular hydrogen bonding, which can reduce polypropylene The orientation of the molecular chain segments makes them arranged regularly, thereby improving the mechanical properties of the polypropylene injection molded product; at the same time, the chiral spiral structure of the chiral silica fiber, through the chiral spiral induction of polypropylene, strengthens the molecular chain The winding can further improve the mechanical properties of polypropylene injection molded products; compared with ordinary silica fibers, chiral silica fibers can more effectively improve the mechanical properties of polypropylene materials and injection molded parts.

Detailed ways

The present invention will be further described below in conjunction with specific embodiments. The following embodiments are only used to explain the technical solutions of the present invention more clearly, and cannot be used to limit the protection scope of the present invention.

Example 1

The present invention provides a chiral silica fiber reinforced foamed polypropylene composite material, which is composed of: 65 wt% of polypropylene resin, 12 wt% of talc, 10 wt% of chiral silica fiber, and 8 wt% of surfactant solution. , Microcellular foaming agent 2.5wt%, xylitol microcapsules 1.5wt%, main antioxidant 0.5wt%, auxiliary antioxidant 0.5wt%.

Among them: polypropylene resin has a flow rate of 45-60g/min under a load of 2.16kg at a temperature of 230°C.

The length of the chiral silica fiber is 3.0-8.0μm and the diameter is 50-80nm; the surfactant solution is a linear sodium alkylbenzene sulfonate aqueous solution with a concentration of 70-80wt%; the chiral silica fiber is surface active Under the action of the aqueous solution of the agent, the intermolecular hydrogen bonds induce chirality, which reduces the orientation of the polypropylene molecular chain segments and makes them regular arrangements, thereby improving the mechanical properties of the polypropylene injection molded product; at the same time, the chiral dioxide The chiral spiral structure of silicon fiber strengthens the entanglement between molecular chains through the chiral spiral induction of polypropylene, which can further improve the mechanical properties of polypropylene injection molded products.

Microcellular foaming agent is a mixture of sodium bicarbonate and citric acid, the mass ratio of the two is 5:7; sodium bicarbonate will produce carbon dioxide gas when heated, which will play a foaming role; the addition of citric acid It can increase the thermal decomposition temperature of sodium bicarbonate and reduce the problem of decomposition and foaming of sodium bicarbonate before the working temperature. At the same time, citric acid also has a certain foaming effect; the particle size of sodium bicarbonate and citric acid are both 3000-5000 Item.

Xylitol is an intermediate temperature phase change material with a phase transition temperature of 92-96℃; when the temperature rises above the phase transition temperature, the intermediate temperature phase change material undergoes a phase change to absorb heat, thereby slowing down or even preventing the increase in the temperature of the microenvironment. Delay the thermal decomposition of sodium bicarbonate, narrow the decomposition temperature range, and improve the foaming effect of sodium bicarbonate.

Talc powder is coated with epoxy resin with a particle size of 10-15μm; the main and auxiliary antioxidant is hindered phenolic antioxidant; the auxiliary antioxidant is thioether antioxidant.

The material is prepared by a conventional method, and the raw materials are weighed and mixed evenly; when used, it is injection molded and foamed according to actual needs.

Example 2

The present invention provides a chiral silica fiber reinforced foamed polypropylene composite material, which consists of 70% by weight of polypropylene resin, 9% by weight of talc, 8% by weight of chiral silica fiber, and 5% by weight of surfactant solution. , Microcellular foaming agent 4wt%, meso-erythritol microcapsules 3wt%, main antioxidant 0.75wt%, auxiliary antioxidant 0.25wt%.

Among them: meso-erythritol is a medium temperature phase change material with a phase transition temperature of 118-124°C; the other materials used have the same properties as in Example 1; the preparation method of the material is the same as in Example 1.

Example 3

The present invention provides a chiral silica fiber reinforced foamed polypropylene composite material, the composition of which is: polypropylene resin 60wt%, talc 16wt%, chiral silica fiber 15wt%, surfactant solution 3wt% , Microcellular foaming agent 2wt%, xylitol microcapsules 2wt%, main antioxidant 1wt%, auxiliary antioxidant 1wt%.

Wherein: the material properties and material preparation methods used are the same as those in Example 1.

Comparative example 1

This comparative example is basically the same as Example 1, except that ordinary silica fiber is added.

The specific composition is: polypropylene resin 65wt%, talc powder 12wt%, ordinary silica fiber 10wt%, surfactant solution 8wt%, microcellular foaming agent 2.5wt%, xylitol microcapsule 1.5wt%, main resistance The oxidant is 0.5% by weight, and the auxiliary antioxidant is 0.5% by weight.

Comparative example 2

This comparative example is basically the same as Example 1, except that no phase change material microcapsules (xylitol microcapsules) are added.

The specific composition is: polypropylene resin 65wt%, talc powder 13.5wt%, chiral silica fiber 10wt%, surfactant solution 8wt%, microcellular foaming agent 2.5wt%, main antioxidant 0.5wt%, auxiliary antioxidant Oxidizing agent 0.5wt%.

Performance Testing:

The foamed polypropylene materials provided in Examples 1-3 and Comparative Examples 1-2 were injection molded into parts and then tested for performance.

Tensile strength test: reference standard: ISO527-2; test condition: span 50mm.

Notched impact strength test: reference standard: ISO179-1; test condition: span 40mm.

Density test: Reference standard: ISO 1183; Test condition: normal temperature.

Melt index test: Reference standard: ISO1133; Test condition: 230℃, 2.16kg.

The test results are as follows:

Example 1: Tensile strength: 25Mpa, Notched impact strength: 39kJ·m ^-2 , Density: 0.75g·cm ^-3 , Melt finger: 44g/10min, Appearance: No air marks on the surface of the part, no tiger skin pattern, no Visually observe the white spots, the weight of the component is reduced by 27%, microscopic: Observe the uniformly closed micropores between 10-100 microns in the middle of the component through the scanning electron microscope.

Example 2: Tensile strength: 23Mpa, notched impact strength: 35KJ·m ^-2 , density: 0.70g·cm ^-3 , melt index: 46g/10min, appearance: no air marks on the surface of the part, no tiger skin pattern, no Visually observe the white spots, the weight of the component is reduced by 30%, microscopic: Observe through the scanning electron microscope that there are uniformly closed micropores between 10-100 microns in the middle of the component.

Example 3: Tensile Strength: 24Mpa, Notched Impact Strength: 37KJ·m ^-2 , Density: 0.79g·cm ^-3 , Melt Finger: 40g/10min, Appearance: No air marks on the surface of the part, no tiger skin pattern, no Visually observe the white spots, the weight of the component is reduced by 25%, microscopic: Observe the uniformly closed micropores between 10-100 microns in the middle of the component through scanning electron microscope.

Comparative Example 1: Tensile Strength: 18Mpa, Notched Impact Strength: 29kJ·m ^-2 , Density: 0.73g·cm ^-3 , Melt Index: 42g/10min, Appearance: No air marks on the surface of the part, no tiger skin pattern, no Visually observe the white spots, the weight of the component is reduced by 27%, microscopic: Observe the uniformly closed micropores between 10-100 microns in the middle of the component through the scanning electron microscope.

Comparative Example 2: Tensile Strength: 24Mpa, Notched Impact Strength: 36KJ·m ^-2 , Density: 0.89g·cm ^-3 , Melt Index: 42g/10min, Appearance: There are air marks and tiger skin patterns on the surface of the parts, and the parts are reduced 18% weight and microscopic: Although there are micropores between 10-100 microns in the middle of the part observed by scanning electron microscope, there are many incomplete formations; compared with Example 1, there are fewer formed holes and uneven distribution.

According to the test results:

(1) The mechanical properties of the injection molded parts of Comparative Example 1 are significantly worse than those of the examples, indicating that the addition of chiral silica fiber can more effectively improve the composite material and its injection molding than ordinary silica fiber. Mechanical properties of components.

(2) The foaming effect of the injection molded parts of Comparative Example 2 is worse than that of Example 1, and the mechanical properties are also slightly worse; this is due to the low decomposition initiation temperature of sodium bicarbonate and the wide decomposition temperature range, which makes polypropylene soften A large amount of decomposition and foaming before the temperature affects the overall foaming effect of the material; the addition of phase change materials improves the heat resistance of sodium bicarbonate, so the thermal decomposition temperature of sodium bicarbonate is increased, and its thermal decomposition is reduced The temperature range reduces unnecessary loss of foaming agent and improves the foaming effect.

The above is based on the ideal embodiment of the present invention as inspiration. Through the above description, relevant personnel can make various changes and modifications within the scope of the technical idea of the present invention. The technical scope of the present invention is not limited to the content in the specification, and the technical scope must be determined according to the scope of the claims.

Claims (11)

A chiral silica fiber reinforced foamed polypropylene composite material, which is characterized in that it comprises the following composition: polypropylene resin, talc, chiral silica fiber, surfactant solution, microcellular foaming agent, phase Variable material microcapsules and additives; the surfactant solution is an aqueous solution of sodium linear alkylbenzene sulfonate. The chiral silica fiber reinforced foamed polypropylene composite material according to claim 1, wherein the auxiliary agent includes a primary antioxidant and a secondary antioxidant. The chiral silica fiber reinforced foamed polypropylene composite material according to claim 2, characterized in that it comprises the following composition: polypropylene resin 60-70wt%, talc 9-16wt%, chiral silica fiber 8-15wt%, surfactant solution 3-8wt%, microcellular foaming agent 2-4wt%, phase change material microcapsule 1.5-3wt%, main antioxidant 0.5-1wt%, auxiliary antioxidant 0.25-1wt%. The chiral silica fiber reinforced foamed polypropylene composite material according to any one of claims 1 to 3, wherein the chiral silica fiber has a length of 3.0-8.0 μm and a diameter of 50-80 nm; The chiral silica fiber reinforced foamed polypropylene composite material according to any one of claims 1 to 3, wherein the microcellular foaming agent is a mixture of sodium bicarbonate and citric acid. The chiral silica fiber reinforced foamed polypropylene composite material according to claim 5, wherein the mass ratio of sodium bicarbonate to citric acid is 5:7. The chiral silica fiber reinforced foamed polypropylene composite material according to any one of claims 1-3, wherein the phase change material is a medium temperature phase change material, and the phase change temperature is 90-130°C. The chiral silica fiber reinforced foamed polypropylene composite material according to any one of claims 1 to 3, wherein the phase change material is xylitol microcapsules and/or meso-erythrus Sugar alcohol microcapsules. The chiral silica fiber reinforced foamed polypropylene composite material according to claim 1, wherein the concentration of the linear sodium alkylbenzene sulfonate aqueous solution is 70-80 wt%. A method for preparing the chiral silica fiber reinforced foamed polypropylene composite material according to any one of claims 1 to 9, characterized in that: the raw materials are mixed uniformly according to the ratio. A foamed polypropylene product, characterized in that it is mixed with the chiral silica fiber reinforced foamed polypropylene composite material according to any one of claims 1 to 9, or the preparation method according to claim 10 The prepared mixture is prepared by injection foam molding.