CN110804273B

CN110804273B - Scratch-resistant fingerprint-resistant spraying-free POM composite material and preparation method thereof

Info

Publication number: CN110804273B
Application number: CN201911006288.2A
Authority: CN
Inventors: 徐凯华
Original assignee: Shanghai Huahe Composite Material Co ltd
Current assignee: Huahe New Material Technology Co ltd
Priority date: 2019-10-22
Filing date: 2019-10-22
Publication date: 2022-06-28
Anticipated expiration: 2039-10-22
Also published as: CN110804273A

Abstract

The invention discloses a scratch-resistant and fingerprint-resistant spraying-free POM composite material and a preparation method thereof, and the scratch-resistant and fingerprint-resistant spraying-free POM composite material is composed of the following raw materials in parts by weight: 30-70 parts of POM resin, 2-5 parts of dispersing agent and 10-30 parts of functionalized master batch, wherein the functionalized master batch comprises the following components in percentage by weight: 3-10 parts of elastic ionomer, 2-6 parts of fullerene C60 powder, 2-8 parts of lipophilicity improver and 3-10 parts of metallic toner. The invention has the beneficial effects that: the novel fullerene C60 powder is adopted to realize the high-efficiency adsorption and surface distribution of the nonpolar micromolecule auxiliary agent, and the pre-dispersion treatment of the masterbatching is beneficial to the synergistic dispersion of various functional auxiliary agents. The obtained POM material has good spraying-free effect, and the surface tension of the material is reduced from 31-33 to about 24-26, so that fingerprint contamination can be effectively prevented; in addition, the scratch resistance of the material is obviously improved, and the POM composite material integrates high surface gloss, high scratch resistance and excellent dirt resistance.

Description

Scratch-resistant fingerprint-resistant spraying-free POM composite material and preparation method thereof

Technical Field

The invention belongs to the technical field of high polymer materials, and particularly relates to a scratch-resistant and fingerprint-resistant spray-free polypropylene composite material and a preparation method thereof.

Background

With the increasing demands on low material cost and environmental protection property in the fields of automobiles, household appliances, industrial electronics, building materials and the like, the defects of the traditional surface spraying post-treatment mode are more obvious, the process is complicated, the product control difficulty is high, the processing cost is high, and the components are highly volatile, so that in recent years, some special appearance effects such as high brightness black, metal texture, diamond luster and the like are gradually obtained by one-step direct injection molding by using the spraying-free material with specific specifications, the environment-friendly condition of a processing site is improved, an additional post-treatment process is not needed, the processing cost of a finished piece is greatly reduced, and the cost performance is high.

Polyformaldehyde (also called polyoxymethenyl, POM for short) as a new functional engineering plastic has high rigidity and high heat resistance similar to polyamide PA materialThe water absorption and the material cost are obviously lower. But because it contains [ -CH ] in the main chain₂-O-]When the repeating units are subjected to melt shearing and mixing, the chain is easily broken and degraded, so that the processing window of the POM homopolymer is narrow (about 10 ℃) and the thermal stability is poor, which is a main problem that the POM material is difficult to popularize and apply in a large range. In recent years, with the continuous improvement of POM polymerization technology, the above disadvantages are improved by the co-polyformaldehyde copolymerized with a small amount of dioxolane, so that an ideal base material is provided for the functional research and popularization of POM materials, especially for the research and application of spraying-free materials.

Compared with the current PA material spraying-free research, the current POM modification scheme is still limited to the optimization and improvement of the conventional performance of the material, for example, the high-rigidity POM composite material provided in CN102311611 takes calcium sulfate whiskers as a reinforcement to further improve rigidity indexes such as tensile strength, bending strength and the like of the material; CN108929517 uses glass fiber and molybdenum disulfide as composite modifier, which further improves the wear resistance of POM material. Although CN109679276 proposes a low-VOC, high-environmental protection, spray-free POM composite material, for the material dedicated for spray-free interior trim parts, the VOC performance improvement is only one of many material indexes in the specification of interior trim parts, and the modification manner of one-step melting and mixing adopted by the material itself has very high limitation, and it is difficult to stably realize the multi-functionalization effect of the material when the formula is complex and the components are numerous.

Disclosure of Invention

The invention aims to fill the blank field of the prior art and provides a scratch-resistant fingerprint-resistant spraying-free POM composite material. An independent reaction kettle pre-dispersion method is adopted to prepare a multifunctional master batch which takes an ionomer as a matrix, fullerene C60 powder as an efficient adsorbent, and has scratch resistance, low polarity and no spraying, and then the master batch, a copolymerization POM matrix, a dispersing aid and other components are subjected to secondary melting and mixing in a screw extruder. The material can realize efficient directional adsorption and arrangement distribution of low-polarity oleophylic auxiliary agent molecules and metallic toner after matching the ionic cluster micro-region of the ionomer with the cage-shaped carbon atom structure in the C60 powder, thereby endowing the surface of the POM material with the characteristics of good low polarity, fingerprint contamination resistance, good scratch resistance effect and the like.

The purpose of the invention is realized by the following technical scheme:

the scratch-resistant and fingerprint-resistant spraying-free POM composite material comprises the following raw materials in parts by weight:

40-80 parts of POM resin,

1-5 parts of a dispersing agent,

10-30 parts of functional master batch,

the functionalized master batch comprises the following components in percentage by weight: 3-10 parts of elastic ionomer, 2-6 parts of fullerene C60 powder, 2-8 parts of lipophilicity improver and 3-10 parts of metallic toner.

The preparation method of the functional master batch comprises the following steps: the preparation method of the functional master batch comprises the following steps: weighing elastic ionomer and fullerene C60 powder according to a proportion, uniformly mixing, putting into a closed reaction kettle, vacuumizing the reaction kettle, filling inert nitrogen to protect the reaction kettle to normal pressure, heating to 180 ℃, keeping the temperature constant, uniformly stirring at a speed of 60 revolutions/min for 10min, continuously stirring for 10min according to a proportion of a lipophilic improver, adding a certain proportion of metallic toner, stirring for 30min, filling nitrogen to pressurize, guiding out, cooling and granulating the molten blend from an outlet at the bottom of the closed reaction kettle to obtain the functionalized master batch.

The POM resin is a copolyoxyformaldehyde resin of trioxymethylene and a small amount of dioxolane, and the melt index MFR of the POM resin is 5-30g/10min under the test conditions of 190 ℃ and 2.16 kg.

The dispersing agent is one or more of calcium stearate, zinc stearate, polyethylene wax, polyester wax, low molecular weight copolyamide wax and the like.

The elastic ionomer is one or more of carboxylic acid ionomer, sulfonic acid ionomer and phosphate ionomer.

The fullerene C60 powder is a cage-like carbon element compound with five-membered rings, the appearance is black powder, and the carbon purity is more than or equal to 98%.

The lipophilic improver is one or more of resin-coated oleic acid, stearic acid, organic silicon assistant and the like.

The metal toner is one or more of aluminum powder, aluminum-silver powder, aluminum-silicon alloy powder, copper-gold powder, nano or metal oxide coated glass microchip composite pigment and the like coated by resin.

The second purpose of the invention is to provide a preparation method of the scratch-resistant and fingerprint-resistant spraying-free POM composite material, which comprises the following steps:

(1) weighing POM resin and a dispersing agent according to the parts by weight, and uniformly mixing to obtain a mixed raw material:

(2) placing the dried mixed raw materials into a main feeding bin of a double-screw extruder which is tightly meshed and rotates in the same direction, and adding the dried mixed raw materials into a machine barrel of the extruder through a feeding screw; and (3) placing the functional master batch into a side feeding bin of a screw rod of the extruder, and adding the functional master batch into a machine barrel of the extruder through a feeding screw rod. The diameter of the screw extruder used was 36mm, the length-diameter ratio L/D was 44, and the temperatures of the zones from the feed port to the head outlet of the main barrel were set as follows: the scratch-resistant and fingerprint-resistant spraying-free POM composite material is obtained by the processes of melt extrusion, granulation, drying and the like at the temperature of 90 ℃, 170 ℃, 180 ℃, 195 ℃, 190 ℃ and at the rotating speed of a main engine of 250 revolutions per minute.

Compared with the prior art, the invention has the following beneficial effects:

1. the preparation method fully considers the preconditions of complex formula, numerous components and relatively difficult dispersion caused by multifunctional improvement of the POM composite material, introduces an independent reaction kettle premixing mode to improve the dispersion condition of key auxiliary agent components (oleophylic improver and metallic toner), simultaneously uses ionomer and fullerene C60 powder with unique structures as base materials, and provides good adsorption effect for small molecular coefficients by using ion cluster micro-regions and C60 cage-shaped atoms, thereby ensuring the modification effect of the POM composite material.

2. The scratch-resistant and fingerprint-resistant spraying-free POM composite material obtained by the technical scheme of the invention not only has good spraying-free appearance performance, but also has the surface glossiness (60 ℃) of more than or equal to 95%, and has no appearance defects such as welding lines, silver wires and the like on the surface of an injection molding sample plate; according to the cross scraping test surface of the material, when the surface grains (smooth surface, fine grain and coarse grain) of three different surfaces are formed, the color difference value delta E after the material is scraped is kept below 1.5, and is reduced by more than 50% compared with that of a conventional spraying-free POM material. In the surface tension test of the material, the test resin of the low-surface-tension POM material improved by the scheme can be reduced to 24-26 at the lowest, and the cleanness (relative fluorescence intensity value and RFU value) of the surface of the spray-free POM material is further contrastively tested by a quantifiable SITA surface roughness tester, the RFU value of the spray-free POM material obtained by the scheme of the invention is greatly reduced to about 50-60 from about 115 of the conventional material, and the scratch resistance times of fingerprints are reduced to about 1/3 in a same ratio.

Detailed Description

The invention is further illustrated by the following specific examples, which are intended to be illustrative only and not limiting.

The raw materials used in the embodiment of the invention are as follows:

POM: the polyoxymethylene copolymer 7520 has a melt index MFR of 30g/10min under a test condition of 190 ℃ and 2.16kg, and is available from Asahi Kasei Co.

Dispersing agent: functional polyester wax CERALENE 694, white particles, viscosity 130-.

An elastic ionomer: the sulfonated styrene-butadiene rubber ionomer has a styrene content of 23 percent and a sulfonation degree of 25mmol of sulfonic acid groups in every 100g of elastomer, and is prepared by self.

Fullerene C60: the cage-shaped nano carbon compound TNC6098 with a five-membered ring structure has the purity of more than or equal to 98 percent, and is formed by Chinese academy organic chemistry Limited company.

Metallic toner-1: super earl 261 diamond pearl powder, surface silica coated, 30um average particle size (D50), 97% or more solid content, Zhejiang Fubock technologies, Inc.

Metallic toner-2: the glass coated silver SG035 and the micron-sized glass microchip surface is plated with nano silver toner, the average grain diameter (D50) is 20um, Shanghai Dynasty times new material Co.

Silver ion antibacterial agent: the gel nano silver solution has the silver particle average particle size (D50) of 1nm, the effective concentration of 2000ppm, the pH value of the solution of 7 +/-0.5 and Yurui chemical.

Lipophilic improver-1: stearic acid micro-tablets 1850 special for rubber and plastic, with octadecyl (C18) content of 48-55%, water content less than or equal to 0.1%, Kaika chemical Co., Ltd.

Lipophilic improver-2: the effective solid content of the polyester modified polydimethylsiloxane organosilicon solution BYK-313 is 15 percent, and the Germany Bikk chemical.

And (3) product performance testing:

and (3) testing the glossiness: the test was carried out according to ISO2813, injection molding specified standard sample plate, CS-380 surface gloss meter, test angle 60 °.

And (3) testing the condition of the spraying-free surface: A355X 100X 3.2mm standard sample plate is injection-molded by adopting a mode of oppositely feeding glue with a left gate and a right gate, the sample plate is placed in a standard environment with 23 ℃ and 50% RH for 48h, and then the condition of a welding line on the surface of the sample plate is observed in a standard inspection lamp box.

Scratch resistance test: three test samples with different surface specifications (smooth surface, fine dermatoglyph and coarse dermatoglyph) are injection-molded according to a PV3951 standard method, the injection molding is carried out on an Erichsen 430P cross grid scratch tester with the load of 10N, and the surface color difference conditions before and after the test samples are compared after the test is finished, so that the color difference value delta E is obtained.

Surface tension test: the surface energy level of the standard Sofial test ink is 20-40dyn/cm according to the standard method of ISO8296, and the test is carried out at normal temperature (23 ℃).

Surface cleanliness and scrub resistance times test: injection molding the spray-free polypropylene composite material into a highlight surface test sample plate with the thickness of 150 multiplied by 100 multiplied by 3.2mm, pressing fingerprints on the highlight surface, and testing the relative fluorescence intensity RFU values of the front surface and the back surface by adopting an SITA surface cleanliness instrument to obtain a surface cleanliness value; wiping the fingerprint with a high-gloss surface by using dust-free cloth, wherein the external wiping load is 10N until the fingerprint is completely wiped, and recording the wiping resistance times of the fingerprint.

Example 1

The elastic ionomer and fullerene C60 powder were weighed in proportion according to the data of example 1 shown in Table 1, and mixed uniformly to obtain a mixed raw material.

Putting the dried mixed raw materials into a closed reaction kettle, vacuumizing the reaction kettle, filling inert nitrogen to protect the reaction kettle to normal pressure, heating to 180 ℃ and keeping the temperature constant, uniformly stirring at a speed of 60 revolutions per minute for 10 minutes, then adding a certain proportion of metallic toner after continuously stirring for 10 minutes according to a proportion of lipophilic improver, stirring for 30 minutes, filling nitrogen to pressurize, guiding out the molten blend from a bottom outlet of the closed reaction kettle, cooling and granulating to obtain the functional master batch.

TABLE 1 formulation of the functionalized masterbatch (Unit: gram)

Example 2

The elastic ionomer and fullerene C60 powder were weighed in proportion according to the data of example 2 shown in Table 1, and mixed uniformly to obtain a mixed raw material.

Example 3

The elastic ionomer and fullerene C60 powder were weighed in proportion according to the data of example 3 shown in Table 1, and mixed uniformly to obtain a mixed raw material.

Example 4

The elastic ionomer and fullerene C60 powder were weighed in proportion according to the data of example 4 shown in Table 1, and mixed uniformly to obtain a mixed raw material.

Example 5

The elastic ionomer and fullerene C60 powder were weighed in proportion according to the data of example 5 shown in Table 1, and mixed uniformly to obtain a mixed raw material.

TABLE 2 recipe table (unit: gram) of scratch-resistant, fingerprint-resistant spray-free POM composite material

	Example 6	Example 7	Example 8	Example 9	Example 10
						POM	77	82	75	79	76
Dispersing agent	2	2	2	2	2
						Functionalized masterbatch of example 1	21
Functionalized masterbatch of example 2		16
						Functionalized masterbatch of example 3			23
Functionalized masterbatch of example 4				19
						Functionalized masterbatch of example 5					22

Example 6

The POM resin and the dispersant were weighed and mixed uniformly according to the data of example 6 shown in table 2, to obtain a mixed raw material.

Placing the dried mixed raw materials into a main feeding bin of a double-screw extruder which is tightly meshed and rotates in the same direction, and adding the dried mixed raw materials into a machine barrel of the extruder through a feeding screw; and (3) placing the functional master batch into a side feeding bin of a screw rod of the extruder, and adding the functional master batch into a machine barrel of the extruder through a feeding screw rod. The diameter of the screw extruder used was 36mm, the length-diameter ratio L/D was 44, and the temperatures of the zones from the feed port to the head outlet of the main barrel were set as follows: the scratch-resistant and fingerprint-resistant spraying-free POM composite material is obtained by the processes of melt extrusion, granulation, drying and the like at the temperature of 90 ℃, 170 ℃, 180 ℃, 195 ℃, 190 ℃ and at the rotating speed of a main engine of 250 revolutions per minute.

Example 7

The POM resin and the dispersant were weighed and mixed uniformly in accordance with the data of example 7 shown in Table 2 to obtain a mixed raw material.

Placing the dried mixed raw material into a main feeding bin of a double-screw extruder which is tightly meshed and rotates in the same direction, and adding the dried mixed raw material into a machine barrel of the extruder through a feeding screw; and (3) placing the functional master batch into a side feeding bin of a screw rod of the extruder, and adding the functional master batch into a machine barrel of the extruder through a feeding screw rod. The diameter of the screw extruder used was 36mm, the length-diameter ratio L/D was 44, and the temperatures of the respective zones from the feed port to the head outlet of the main barrel were set as follows: the scratch-resistant and fingerprint-resistant spraying-free POM composite material is obtained by the processes of melt extrusion, granulation, drying and the like at the temperature of 90 ℃, 170 ℃, 180 ℃, 195 ℃, 190 ℃ and at the rotating speed of a main engine of 250 revolutions per minute.

Example 8

The POM resin and the dispersant were weighed and mixed uniformly in accordance with the data of example 8 shown in Table 2 to obtain a mixed raw material.

Example 9

The POM resin and the dispersant were weighed and mixed uniformly in accordance with the data of example 9 shown in Table 2 to obtain a mixed raw material.

Placing the dried mixed raw materials into a main feeding bin of a double-screw extruder which is tightly meshed and rotates in the same direction, and adding the dried mixed raw materials into a machine barrel of the extruder through a feeding screw; and (3) placing the functional master batch into a side feeding bin of a screw rod of the extruder, and adding the functional master batch into a machine barrel of the extruder through a feeding screw rod. The diameter of the screw extruder used was 36mm, the length-diameter ratio L/D was 44, and the temperatures of the zones from the feed port to the head outlet of the main barrel were set as follows: the scratch-resistant and fingerprint-resistant spraying-free POM composite material is obtained by the processes of melt extrusion, granulation, drying and the like at the temperature of 90 ℃, 170 ℃, 180 ℃, 195 ℃, 190 ℃ and at the rotating speed of a main engine of 250 revolutions per minute

Example 10

The POM resin and the dispersant were weighed according to the data of example 10 shown in table 2, and mixed uniformly to obtain a mixed raw material.

Comparative example 1

Weighing 92 g of POM resin, 2 g of dispersing agent and 6 g of metallic toner-2, and uniformly mixing to obtain a mixed raw material:

placing the dried mixed raw materials into a main feeding bin of a double-screw extruder which is tightly meshed and rotates in the same direction, and adding the dried mixed raw materials into a machine barrel of the extruder through a feeding screw; the diameter of the screw extruder used was 36mm, the length-diameter ratio L/D was 44, and the temperatures of the zones from the feed port to the head outlet of the main barrel were set as follows: the spraying-free POM composite material is obtained by the processes of melt extrusion, granulation, drying and the like at the temperature of 90 ℃, 170 ℃, 180 ℃, 195 ℃, 190 ℃ and at the rotating speed of a main engine of 250 revolutions per minute.

TABLE 3 test results of scratch-resistant, fingerprint-resistant spray-free POM composite materials

Comparing the material test data of each example and comparative example in table 3, it can be seen that the conventional spray-free POM composite represented by comparative example 1 has a high surface gloss (86), but the surface condition of the material is poor, especially the silver silk phenomenon is very obvious, and the color difference value Δ E is above 2.0 in scratch resistance tests of three different specifications of smooth surface, fine leather grain and coarse leather grain, and the root cause of the poor condition is the poor distribution condition of metallic toner in the material. With the addition of the fullerene C60, which is a cage-shaped carbon structure material with high adsorption capacity, the silver filament condition on the surface of the POM material is obviously improved (examples 7, 9 and 10), the color difference value of the surface of the POM material after multiple scratches can be reduced to 0.9-1.2 (example 10), and more importantly, the glossiness of the surface of the POM material is also improved to a level of more than 95 at the same time, so that the POM composite material has high scratch resistance, high gloss and excellent spraying-free effect.

Comparing the surface tension test and the fingerprint stain resistance degree of each example and comparison, the conventional POM material is formed by condensation polymerization of aldehyde groups with high polarity, so the surface tension of the POM material is as high as 32, the POM material is easily polluted by fingerprints and is not easy to wipe off, the performance indexes of the POM material are obviously improved along with the addition of the low surface tension auxiliary agent, the surface tension of the POM material is reduced to about 24, and the polluted fingerprints can be completely eliminated after 5 times of wiping, which is reduced by 2/3 compared with 13 times of wiping in comparative example 1.

According to the scratch-resistant and fingerprint-resistant spraying-free POM composite material and the preparation method thereof, the problems that POM spraying-free is frequently encountered, such as surface silver wires, welding lines and the like are solved, the key components are efficiently dispersed and fixedly distributed by adding the efficient adsorbent with the characteristic structure, the excellent characteristics of the material, such as scratch resistance and fingerprint resistance, are synergistically improved while high gloss is maintained, the POM composite material is extremely high in cost performance and outstanding in multifunctional characteristics, and the current situation that the current POM spraying-free and multifunctional research is insufficient can be effectively made up.

Claims

1. A scratch-resistant and fingerprint-resistant spraying-free POM composite material is characterized in that: the feed comprises the following raw materials in parts by weight:

40-80 parts of POM resin,

1-5 parts of a dispersing agent,

10-30 parts of a functional master batch,

the functionalized master batch comprises the following components in parts by weight: 3-10 parts of elastic ionomer, 2-6 parts of fullerene C60 powder, 2-8 parts of lipophilic improver and 3-10 parts of metal toner.

2. The scratch-resistant fingerprint-resistant spray-free POM composite material as claimed in claim 1, wherein the coating comprises the following components in percentage by weight: the preparation method of the functional master batch comprises the following steps: weighing elastic ionomer and fullerene C60 powder according to a proportion, uniformly mixing, putting into a closed reaction kettle, vacuumizing the reaction kettle, filling inert nitrogen to protect the reaction kettle to normal pressure, heating to 180 ℃, keeping the temperature constant, uniformly stirring at a speed of 60 revolutions/min for 10min, adding a proportion of lipophilic improver, continuously stirring for 10min, adding a proportion of metallic toner, stirring for 30min, filling nitrogen to pressurize, guiding out, cooling and granulating the molten blend from an outlet at the bottom of the closed reaction kettle to obtain the functionalized master batch.

3. The scratch-resistant fingerprint-resistant spray-free POM composite material as claimed in claim 1, wherein: the POM resin is a copolyoxyformaldehyde resin of trioxymethylene and a small amount of dioxolane, and the melt index MFR of the POM resin is 5-30 g/10min under the test conditions of 190 ℃ and 2.16 kg.

4. The scratch-resistant fingerprint-resistant spray-free POM composite material as claimed in claim 1, wherein the coating comprises the following components in percentage by weight: the dispersing agent is one or more of calcium stearate, zinc stearate, polyethylene wax, polyester wax and low molecular weight copolyamide wax.

5. The scratch-resistant fingerprint-resistant spray-free POM composite material as claimed in claim 1, wherein: the elastic ionomer is one or more of carboxylic acid ionomer, sulfonic acid ionomer and phosphate ionomer.

6. The scratch-resistant fingerprint-resistant spray-free POM composite material as claimed in claim 1, wherein: the fullerene C60 powder is a cage-like carbon element compound with five-membered rings, the appearance is black powder, and the carbon purity is more than or equal to 98%.

7. The scratch-resistant fingerprint-resistant spray-free POM composite material as claimed in claim 1, wherein: the lipophilic improver is one or more of resin-coated oleic acid, stearic acid and organic silicon assistant.

8. The scratch-resistant fingerprint-resistant spray-free POM composite material as claimed in claim 1, wherein: the metal toner is one or more of aluminum powder, aluminum-silver powder, aluminum-silicon alloy powder and copper-gold powder coated by resin.

9. The process for preparing a scratch-resistant fingerprint-resistant spray-free POM composite material according to any one of claims 1 to 8, characterized by comprising the steps of:

(1) weighing POM resin and a dispersing agent according to the weight parts, and uniformly mixing to obtain a mixed raw material;

(2) placing the dried mixed raw materials into a main feeding bin of a double-screw extruder which is tightly meshed and rotates in the same direction, and adding the dried mixed raw materials into a machine barrel of the extruder through a feeding screw; placing the functional master batch in a side feeding bin of a double-screw extruder, and adding the functional master batch into a machine barrel of the extruder through a feeding screw; the diameter of the screw extruder used was 36mm, the length-diameter ratio L/D was 44, and the temperatures of the zones from the feed port to the head outlet of the main barrel were set as follows: the scratch-resistant and fingerprint-resistant spraying-free POM composite material is obtained by the processes of melt extrusion, granulation and drying at the temperature of 90 ℃, 170 ℃, 180 ℃, 195 ℃, 190 ℃ and at the rotating speed of a main engine of 250 revolutions per minute.