CN111925591A

CN111925591A - Scratch-resistant polypropylene material and preparation method thereof

Info

Publication number: CN111925591A
Application number: CN202010765523.0A
Authority: CN
Inventors: 熊志文; 叶开元
Original assignee: Ningbo Jingcheng Plastic Products Co ltd
Current assignee: Ningbo Jingcheng Plastic Products Co ltd
Priority date: 2020-08-01
Filing date: 2020-08-01
Publication date: 2020-11-13
Anticipated expiration: 2040-08-01
Also published as: CN111925591B

Abstract

The invention discloses a scratch-resistant polypropylene material and a preparation method thereof, which relate to the technical field of high polymer materials and comprise the following components in parts by weight: 60-75 parts of polypropylene, 20-35 parts of modified chitosan fiber, 10-15 parts of an ore filler, 1-2 parts of a silane coupling agent, 0.5-1 part of a lubricant and 3-5 parts of a compatilizer, wherein the ore filler is prepared by mixing kieselguhr, quartz and calcium carbonate in a weight ratio of 3:3: 2; weighing the materials according to the specification, uniformly mixing, adding the obtained mixture into a screw extruder for melt extrusion, cooling by cooling water after extrusion, and then shearing and granulating to obtain the scratch-resistant polypropylene material. The polypropylene prepared by the method has good scratch resistance.

Description

Scratch-resistant polypropylene material and preparation method thereof

Technical Field

The invention relates to the field of high polymer materials, in particular to a scratch-resistant polypropylene material and a preparation method thereof.

Background

Plastic products are high molecular compounds made of plastics and polymerized by polyaddition or polycondensation, commonly known as plastics or resins, which may consist of synthetic resins and additives such as fillers, plasticizers, lubricants, etc. The plastic products are ubiquitous in our lives, and compared with metal, stone and wood, the plastic products have the advantages of low cost, strong plasticity and the like, and are widely applied to national economy.

Polypropylene is a non-toxic, odorless and tasteless milky-white high-crystalline polymer, which is particularly stable to water, has a water absorption of only 0.01% in water, a molecular weight of about 8-15 ten thousand, good moldability, good surface gloss of the product, and good chemical stability, and thus occupies a large specific gravity in plastic products. Although polypropylene has many advantages, polypropylene has poor scratch resistance, and scratches are generated on the surface of a product due to collision during assembly, transportation, use and the like, which affects the beauty of the product, thereby limiting the application thereof.

In order to overcome the defects, the Chinese patent application with the prior publication number of CN108070157A discloses a high-hardness scratch-resistant material and a preparation method thereof, wherein the material comprises the following components in parts by weight: 22-42 parts of polypropylene resin, 14-23 parts of POE (polyolefin elastomer), 9-17 parts of inorganic filler, 4-12 parts of modified titanium dioxide, 1.3-6.5 parts of scratch-resistant assistant, 0.3-1.5 parts of compatilizer, 0.5-1.2 parts of plasticizer and 0.3-1 part of antioxidant, wherein the scratch-resistant assistant is erucamide. The material prepared by adding the formic acid amide can effectively improve the scratch resistance of the material and provide long-acting scratch resistance protection for the material.

However, erucamide migrates to the surface of the product after application, and the phenomena of blooming, whitening and the like appear, so that the aesthetic feeling of the product is reduced.

Disclosure of Invention

In view of the defects in the prior art, the first object of the present invention is to provide a scratch resistant polypropylene material, which has the advantages of good scratch resistance and no influence on the appearance of the polypropylene material.

The second purpose of the invention is to provide a preparation method of the scratch-resistant polypropylene material, which has the advantages of simple preparation method and suitability for popularization and production.

In order to achieve the first object, the invention provides the following technical scheme:

the scratch-resistant polypropylene material comprises the following components in parts by weight: 60-75 parts of polypropylene, 20-35 parts of modified chitosan fiber, 10-15 parts of an ore filler, 1-2 parts of a silane coupling agent, 0.5-1 part of a lubricant and 3-5 parts of a compatilizer, wherein the ore filler is prepared by mixing kieselguhr, quartz and calcium carbonate according to the weight ratio of 3: 2.

By adopting the technical scheme, under the action of the lubricant, the modified chitosan fiber can be well distributed in the polypropylene material, the modified chitosan fiber can have a reinforcing effect on the material, so that the scratch resistance is improved, under the action of the silane coupling agent, the group at one end of the silane coupling agent can react with the hydroxyl on the surface of the modified chitosan fiber, and the other end of the silane coupling agent can form a hydrogen bond and a chemical bond with a high molecular chain segment of the polypropylene, so that the silane coupling agent can play a role of a bridge, the connecting force between the modified chitosan fiber and the polypropylene material is improved, the reinforcing effect of the modified chitosan fiber on the polypropylene material is further improved, when the polypropylene material is subjected to the acting force of external scraping, the stress can be effectively transmitted through the modified chitosan fiber, the phenomenon of stress concentration is reduced, and the center and the depth of a scratch are smoother, the shoulder ridge of the scratch is lower, so that the damage of the scratch to the surface of the material is weakened to a greater extent, and the scratch resistance of the polypropylene material is improved;

in addition, the polypropylene material also comprises an ore filler, the ore filler comprises diatomite, quartz and calcium carbonate, and the addition of the ore filler can play a good heterogeneous nucleation role, so that better crystallinity is brought to the polypropylene, and the addition of the ore filler can play a role in enhancing the hardness of the polypropylene material, so that the scratch resistance of the polypropylene material is improved, meanwhile, the calcium carbonate has stronger adsorption capacity, so that each component in the polypropylene material can be firmly adsorbed, the migration of the components to the surface of the polypropylene material is reduced, and the modified chitosan fiber is more stable in the system; furthermore, the chitosan fiber has more active hydroxyl and amino groups and higher chemical activity, so that the polypropylene material is endowed with excellent dyeing performance, and the polypropylene material can be dyed by using various dyes such as active, acidic and reductive dyes after the chitosan is added into the polypropylene material, so that the applicability of the material is improved.

Further, the modified chitosan fiber is prepared by the following method; dissolving 3 parts of silver nitrate into 100 parts of deionized water, adding 15 parts of chitosan fiber into a silver nitrate solution, uniformly stirring, adding 3 parts of prepared sodium borohydride solution into the solution, and filtering, cleaning and drying to obtain the modified chitosan fiber.

Through adopting above-mentioned technical scheme, because have the high amino nitrogen of activity on the crust amine fibre, can with the complexation between the silver ion, make silver ion absorption on the crust amine fibre, can reduce the silver ion into nanometer silver granule under sodium borohydride's reducing action, connect through the coordinate bond between silver granule and the crust amine fibre, thereby make silver granule be difficult to break away from the crust amine fibre, crust amine fibre after the silver modification has fine antibiotic effect, can give polypropylene materials certain antibacterial capacity, thereby improve polypropylene materials's suitability.

Further, the chitosan fiber is previously treated as follows: soaking chitosan fiber in alkali solution with pH of 9-11 for 20min, taking out, washing with water and drying.

By adopting the technical scheme, after the chitosan fiber is treated by the alkali liquor, pectin, lignin, hemicellulose and other low molecular impurities in the chitosan fiber can be dissolved out, the rotating angle of the microfiber is reduced, the surface of the chitosan fiber can be roughened to form a plurality of cavities, the fixing effect on silver particles is improved, and the interface bonding force between the fiber and a polypropylene material is also improved; in addition, the surface active points of the chitosan fiber after the alkalization treatment are increased, and the reaction capability of the chitosan fiber and a silane coupling agent is improved, so that the connecting force between the modified chitosan fiber and the polypropylene chain segment is improved, and the material reinforcing effect is better.

Further, the ore filler is prepared by adopting the following method: dissolving 15 parts of sodium carbonate in 100 parts of deionized water, adding 20 parts of diatomite and 10 parts of quartz into the solution, adding 20 parts of zinc nitrate into the solution while stirring, washing and drying the obtained particles, and roasting for 3 hours at 500 ℃.

Furthermore, the surfaces of the diatomite and the quartz have more pores, zinc nitrate is added into a sodium carbonate solution and can react on the surfaces and the pores of the ore fillers to generate zinc carbonate, and a nano zinc oxide layer is formed after the zinc nitrate solution is baked at high temperature, and the nano zinc oxide has the capacity of absorbing and scattering ultraviolet rays, so that the polypropylene material is endowed with good ultraviolet resistance, and the durability of the material is improved.

Further, the compatilizer is formed by mixing PP-g-MAH and POE-g-MAH in a weight ratio of 1: 1.

By adopting the technical scheme, the PP-g-MAH and the POE-g-MAH are compounded for use, so that the compatibility between each component and the polypropylene chain segment can be improved, the components are distributed more uniformly, the acting force between each component and the polypropylene chain segment is higher, and the polypropylene material has better mechanical property.

Further, the lubricant is ethylene bis stearamide.

By adopting the technical scheme, the ethylene bis-stearamide can promote the distribution of the ore filler in the polypropylene material and can also reduce the friction coefficient of the surface of the polypropylene material, so that the scratch resistance of the polypropylene material is further improved.

Further, the polypropylene material also comprises 0.5-0.8 part of antioxidant, the antioxidant is a mixture of phytic acid and luteolin, and the weight ratio of the phytic acid to the luteolin is 1: 1.

By adopting the technical scheme, the luteolin belongs to flavonoid compounds, has more phenolic hydroxyl groups and has good oxidation resistance, the luteolin and metal ions have certain complexing effect and synergistic effect with chitosan, the catalytic effect of metal ions such as iron and copper can be eliminated, the luteolin can supply one hydrogen atom of a peroxide free radical to convert the peroxide free radical into hydroperoxide, so that the material has oxidation resistance, and the phytic acid can be synergistic with the luteolin to further improve the oxidation resistance, so that the obtained polypropylene material has good oxidation resistance.

In order to achieve the second object, the invention provides the following technical scheme:

the preparation method of the scratch-resistant polypropylene material is characterized by comprising the following steps:

(1) respectively weighing polypropylene, modified chitosan fiber, ore filler, silane coupling agent, lubricant, compatilizer and antioxidant according to the specification, and uniformly mixing;

(2) and (2) adding the mixture obtained in the step (1) into a screw extruder for melt extrusion, cooling by cooling water after extrusion, and then shearing and granulating to obtain the polypropylene material.

By adopting the technical scheme, the scratch-resistant polypropylene material can be obtained, and the obtained polypropylene material has good ultraviolet resistance and oxidation resistance.

In conclusion, the invention has the following beneficial effects:

firstly, because the modified chitosan fiber is added in the polypropylene material, the acting force of the polypropylene material can be effectively transferred under the condition of external force, and the generation of scratches is reduced, so that the scratch resistance of the polypropylene material is improved;

secondly, the mineral filler is added into the polypropylene material, and the mineral filler can improve the hardness of the polypropylene material, so that the scratch resistance of the polypropylene material is further improved.

Detailed Description

The present invention will be described in further detail with reference to examples.

The raw materials of the following preparation examples and examples are shown in table 1;

polypropylene (K8303)	Yingcang plastification Co Ltd of Yuyao City
		Chitosan fibers	QINGDAO MINGYUE BIOMEDICAL MATERIALS Co.,Ltd.
Silane coupling agent (KH560)	Jinan nation chemical Co., Ltd
		Diatomite	SHANGHAI MACKLIN BIOCHEMICAL Co.,Ltd.
Quartz crystal	SHANGHAI ALADDIN BIOCHEMICAL TECHNOLOGY Co.,Ltd.
		Calcium carbonate	SHANGHAI ALADDIN BIOCHEMICAL TECHNOLOGY Co.,Ltd.
Silver nitrate	SHANGHAI ALADDIN BIOCHEMICAL TECHNOLOGY Co.,Ltd.
		Sodium borohydride	SHANGHAI ALADDIN BIOCHEMICAL TECHNOLOGY Co.,Ltd.
Sodium hydroxide	SHANGHAI ALADDIN BIOCHEMICAL TECHNOLOGY Co.,Ltd.
		Sodium carbonate	SHANGHAI ALADDIN BIOCHEMICAL TECHNOLOGY Co.,Ltd.
Zinc nitrate	SHANGHAI ALADDIN BIOCHEMICAL TECHNOLOGY Co.,Ltd.
		PP-g-MAH	Dongguan Shanghao Plastic materials Co Ltd
POE-g-MAH	Yucheng plastication Co Ltd of Dongguan City
		Ethylene bis stearamide	Jinan Yuanxiang chemical Co Ltd
Phytic acid	Bailingwei Tech Co Ltd
		Luteolin	Changsha Shanghai Biotech Co., Ltd

Preparation example 1

Preparing modified chitosan fiber: weighing 3 parts of silver nitrate, dissolving in 100 parts of deionized water, and uniformly stirring; weighing 15 parts of cut chitosan fiber, adding the chitosan fiber into the silver nitrate solution, and continuously stirring; weighing 1 part of sodium borohydride, dissolving the sodium borohydride in 100 parts of deionized water to obtain a sodium borohydride solution, weighing 3 parts of the sodium borohydride solution, adding the sodium borohydride solution into the silver nitrate solution, continuously stirring, taking out the chitosan fiber after reacting for 2min, washing the chitosan fiber for multiple times by using distilled water, and drying to obtain the modified chitosan fiber.

Preparation example 2

Preparing the ore filler: weighing 15 parts of sodium carbonate, dissolving in 100 parts of deionized water, weighing 10 parts of diatomite and 10 parts of quartz, adding into a sodium carbonate solution, weighing 20 parts of zinc nitrate, adding into the solution, continuously stirring, washing and drying the obtained diatomite and quartz particles after 20min, baking for 3h at 500 ℃, mixing the diatomite, the quartz and the calcium carbonate according to the weight ratio of 3:2, and obtaining the ore filler. Before use, the diatomite, the quartz and the calcium carbonate are ball-milled and sieved by a 1200-mesh sieve for use.

Examples

Example 1

Weighing 60 parts of polypropylene, 20 parts of modified chitosan fiber, 10 parts of ore filler, 1 part of silane coupling agent, 0.5 part of lubricating agent, 3 parts of compatilizer and 0.5 part of antioxidant, and uniformly mixing; and adding the obtained mixture into a screw extruder for melt extrusion, controlling the temperature of the front section of the screw extruder to be 190 ℃, the temperature of the middle section of the screw extruder to be 185 ℃, the temperature of the rear section of the screw extruder to be 170 ℃, and the length-diameter ratio of the screw to be 45: 1, cooling the strip material by cooling water after extrusion, and then shearing and granulating to obtain the scratch-resistant polypropylene material.

Wherein the lubricant is ethylene bis stearamide, the compatilizer is formed by mixing PP-g-MAH and POE-g-MAH with the weight ratio of 1:1, and the antioxidant is a mixture of phytic acid and luteolin with the weight ratio of 1: 1.

Examples 2 to 6 the process steps are the same as in example 1, with the quality of the components adjusted on the basis of the method of example 1.

The components of examples 1-6 and the mass (in parts) of each component are shown in table 2:

table 2 table of the amounts of examples 1 to 6

Comparative example

Comparative example 1

The comparative example is different from example 2 in that the modified chitosan fiber is not added to the polypropylene material, and other components and process steps are the same as those of example 2.

Comparative example 2

The difference between the comparative example and example 2 is that the chitosan fiber was not modified with silver nitrate and the other components and process steps were the same as in example 2.

Comparative example 3

The present comparative example differs from example 2 in that no mineral filler is added to the polypropylene component and the other components and process steps are the same as in example 2.

Comparative example 4

The comparative example differs from example 3 in that the diatomaceous earth and quartz surfaces are not loaded with zinc oxide particles, and the other components and process steps are the same as in example 3.

Comparative example 5

The present comparative example differs from example 4 in that no antioxidant is added and the other components and process steps are the same as in example 4.

Comparative example 6

This comparative example differs from example 4 in that no silane coupling agent is added and the other components and process steps are the same as in example 4.

Detection method/test method

Scratch resistance test: the grid scratch test method comprises the steps of scratching a grid on the surface of a material by a fixed load and a fixed spacing distance, recording and evaluating the color change of a scratch, and representing the scratch resistance of the surface of the material through the whitening degree of the scratch. A cross-shaped notch testing machine with instrument force information is adopted to scratch a grid, the load is 10N, the L value (the depth of reaction color) before and after scraping is tested through a color measuring instrument, the delta L is calculated, and the larger the delta L value is, the more obvious the color is whitish after scraping is shown, and the worse the scraping resistance performance of the material is.

And (3) testing color fastness: dyeing a sample by using a dye, soaking the sample in water for 8 hours, and performing color fastness detection according to a GB/T251-2008 method;

and (3) testing antibacterial performance: performing an antibacterial performance test on the sample by referring to QB/T2591-2003A, wherein the test strain is escherichia coli; heat-resistant air aging: the method is carried out according to the detection method in GB/T9871-1988 (100 ℃ is multiplied by 72h), and the tensile strength retention rate after the air oxidation aging test is tested, wherein the tensile strength retention rate is multiplied by 100 percent (the tensile strength after the air aging/the original tensile strength);

rockwell hardness: GB/T3398.2-2008;

ultraviolet aging resistance test; irradiating the sample by using an ultraviolet accelerated aging test box for 80h, and testing the tensile strength retention rate before and after ultraviolet aging resistance, wherein the tensile strength retention rate is (tensile strength after ultraviolet aging/tensile strength before ultraviolet aging resistance) multiplied by 100%;

performance test tables of examples 1 to 6 and comparative examples 1 to 6

As can be seen from the above table, by comparing the example 2 with the comparative example 1, the scratch resistance of the polypropylene material is greatly reduced in the component without adding the modified chitosan fiber, mainly because the chitosan fiber plays a role in transferring stress in the system, and can effectively transfer the scratch force to the surrounding high molecular chain segment, so that the resistance effect to the scratch force is improved, and the generation of the scratch is greatly reduced.

It can be seen from the comparison between example 2 and comparative example 2 that the polypropylene material has a certain antibacterial property without silver modification of the chitosan fiber, mainly because the amino cation in the chitosan molecule is combined with sialic acid or phospholipid anion which adsorbs the bacterial cell wall, and then the cation is combined with the anion, which restricts the freedom of the cell and then hinders the growth of the cell. Meanwhile, the low molecules of the chitosan can also penetrate into the cell wall of the bacteria to prevent the transfer of genetic factors from DNA to RNA and prevent the development and growth of the bacteria. Thereby the polypropylene material has antibacterial property; and the Rockwell hardness shows that the Rockwell hardness of the chitosan fiber modified by the silver particles can be slightly improved, mainly because the addition of the metal particles can improve the mechanical property of the chitosan fiber, thereby playing a role in improving the hardness of the polypropylene material.

It can be seen from the comparison between example 2 and comparative example 3 that the rockwell hardness of the material is greatly reduced when no mineral filler is added, mainly the mineral filler plays a role in increasing the strength, and also can play a role in nucleating agent, so that the crystallinity of the polypropylene material is improved, and the material has better scratch resistance.

It can be seen from the comparison between example 3 and comparative example 4 that after the surface of the diatomite and the quartz is loaded with zinc oxide, the tensile strength retention rate after the ultraviolet test is higher, mainly because the zinc oxide has the capacity of absorbing and scattering ultraviolet rays, thereby improving the ultraviolet resistance of the material. And as can be seen by comparing example 4 with comparative example 5, the addition of an antioxidant enables the ageing resistance of the material.

It can be seen from the comparison between example 4 and comparative example 6 that the addition of the silane coupling agent can improve the interface compatibility between the chitosan fiber and the polypropylene chain segment, so that the scratch resistance of the chitosan fiber to the material is enhanced more effectively, and the chitosan fiber can be distributed more uniformly in the system.

The present embodiment is only for explaining the present invention, and it is not limited to the present invention, and those skilled in the art can make modifications of the present embodiment without inventive contribution as needed after reading the present specification, but all of them are protected by patent law within the scope of the claims of the present invention.

Claims

1. The scratch-resistant polypropylene material is characterized by comprising the following components in parts by weight: 60-75 parts of polypropylene, 20-35 parts of modified chitosan fiber, 10-15 parts of an ore filler, 1-2 parts of a silane coupling agent, 0.5-1 part of a lubricating agent and 3-5 parts of a compatilizer, wherein the ore filler is prepared by mixing kieselguhr, quartz and calcium carbonate in a weight ratio of 3:3: 2.

2. The scratch-resistant polypropylene material as claimed in claim 1, wherein the modified chitosan fiber is prepared by the following method; dissolving 3 parts of silver nitrate into 100 parts of deionized water, adding 15 parts of chitosan fiber into a silver nitrate solution, uniformly stirring, adding 3 parts of prepared sodium borohydride solution into the solution, and filtering, cleaning and drying to obtain the modified chitosan fiber.

3. The scratch-resistant polypropylene material according to claim 2, wherein the chitosan fiber is previously treated by: soaking the chitosan fiber in an alkali solution with the pH =9-11 for 20min, taking out, washing and drying.

4. The scratch-resistant polypropylene material as claimed in claim 1, wherein the mineral filler is prepared by the following steps: dissolving 15 portions of sodium carbonate in 100 portions of deionized water, adding 20 portions of diatomite and 10 portions of quartz into the above-mentioned solution, adding 20 portions of zinc nitrate into the above-mentioned solution, continuously stirring them, washing and drying the obtained granules, then adding the above-mentioned granules into 500 portions of water^oAnd C, roasting for 3 hours.

5. The scratch-resistant polypropylene material as claimed in claim 1, wherein the compatibilizer is a mixture of PP-g-MAH and POE-g-MAH at a weight ratio of 1: 1.

6. The scratch-resistant polypropylene material of claim 1, wherein the lubricant is ethylene bis stearamide.

7. The scratch-resistant polypropylene material as claimed in claim 1, wherein the polypropylene material further comprises 0.5-0.8 part of antioxidant, the antioxidant is a mixture of phytic acid and luteolin, and the weight ratio of the phytic acid to the luteolin is 1: 1.

8. The method for preparing a scratch resistant polypropylene material according to any one of claims 1 to 7, comprising the steps of: