CN114685893A

CN114685893A - Low-density and good-mechanical-property spray-free polypropylene composition and preparation method and application thereof

Info

Publication number: CN114685893A
Application number: CN202210333915.9A
Authority: CN
Inventors: 俞飞; 陈平绪; 叶南飚; 马金成; 吴国峰
Original assignee: Kingfa Science and Technology Co Ltd
Current assignee: Kingfa Science and Technology Co Ltd
Priority date: 2022-03-31
Filing date: 2022-03-31
Publication date: 2022-07-01

Abstract

The invention discloses a spraying-free polypropylene composition with low density and good mechanical property, a preparation method and application thereof. The spray-free polypropylene composition comprises the following components in parts by weight: 50-70 parts of PP resin, 8-16 parts of POE resin, 15-25 parts of whiskers, 1-3 parts of a compatilizer, 2-5 parts of a metal effect pigment and 1-3 parts of a foaming agent master batch. By introducing POE resin and crystal whiskers, the rigidity and toughness of the polypropylene material are synchronously improved, and the shrinkage rate of the prepared spray-free polypropylene composition is similar to that of an ABS material. The addition of the metal effect pigment enables the polypropylene material to have the spraying-free metal effect and keep low density; the foam master batch further reduces the density of the material in the spray-free polypropylene composition.

Description

Low-density and good-mechanical-property spray-free polypropylene composition and preparation method and application thereof

Technical Field

The invention relates to the technical field of high polymer materials, in particular to a spraying-free polypropylene composition with low density and good mechanical property, and a preparation method and application thereof.

Background

In order to meet the increasing requirements of automobile appearance, ABS materials are used for automobile interior and exterior decorations in a large scale, and metal luster is generated through electroplating, so that the aesthetic requirements are met. However, the cost of the ABS material is high, the processing cost can be further increased by the electroplating process, and the prior art reports that the electroplating ABS material is replaced by compounding other components with polypropylene resin.

Generally, when other materials are used to replace ABS materials, the closer the shrinkage rate between the replacement material and the ABS is, the better the shrinkage rate is, so that the original ABS mold can be used for injection molding.

The prior art discloses an antistatic spraying-free polypropylene composite material with low linear thermal expansion coefficient and a preparation method thereof, wherein polypropylene and mineral filling and toughening agents are compounded to improve the mechanical property of the composite material, and functional additives are added to improve the crystallization speed and the crystallinity of the material and reduce the post-shrinkage of the product; however, the composite material has high material density due to large mineral filling amount, the shrinkage rates of polypropylene and ABS are different, and after the mineral filling and toughening agent is compounded, the shrinkage rate of the prepared composite material still has a large difference with that of the ABS material, and the composite material is difficult to be injection molded by using the original ABS mold. The polypropylene material comprises components such as polypropylene, mineral powder, a compatilizer, a foaming agent, metal pigment and the like, and although the material has a spraying-free effect and low density, the mechanical property of the polypropylene material is poor, and particularly the notched izod impact strength is low.

Therefore, it is necessary to develop a spray-free polypropylene composition with low density, good mechanical properties and shrinkage similar to ABS.

Disclosure of Invention

The invention provides a spray-free polypropylene composition with low density and good mechanical property, aiming at overcoming the defects of high density, poor mechanical property and overlarge difference between shrinkage and ABS in the prior art.

Another object of the present invention is to provide a process for preparing the above spray-free polypropylene composition.

Another object of the present invention is to provide the use of the above spray-free polypropylene composition.

In order to solve the technical problems, the invention adopts the technical scheme that:

a low-density and good-mechanical-property spray-free polypropylene composition comprises the following components in parts by weight:

50-70 parts of PP resin,

8-16 parts of POE resin,

15-25 parts of whisker, wherein the whisker is selected from the group consisting of,

1-3 parts of a compatilizer,

2-5 parts of a metal effect pigment,

1-3 parts of foaming agent master batch.

The POE resin is uniformly distributed in a strip shape in a PP resin matrix and is used as a stress concentration point, and when the material is subjected to external force, a large amount of silver lines and shear bands are initiated, so that the toughening effect is achieved. The whisker is combined with PP resin through intermolecular force under the action of a compatilizer, and has excellent rigidity increasing effect.

The inventor researches and discovers that POE resin and whiskers contribute to synchronous improvement of rigidity and toughness of the material in a PP resin system. Meanwhile, the shrinkage rate of the prepared spraying-free polypropylene composition is similar to that of an ABS material through the synergistic effect of POE resin with specific content and crystal whiskers.

Preferably, the mass ratio of the POE resin to the whisker is 1: (1.5-2).

Within the above mass ratio range, the spray-free polypropylene composition has a shrinkage rate closer to that of the ABS material.

The addition of the metal effect pigment enables the polypropylene material to have the metal spraying-free effect, thereby saving the density increase and the cost increase caused by the electroplating process. The foaming agent master batch further reduces the density of the material in the spray-free polypropylene composition. The addition of the compatilizer enhances the binding force between the POE resin, the crystal whisker, the metal effect pigment and the foaming agent master batch and the polypropylene resin matrix, and the components have synergistic interaction, so that the spray-free polypropylene composition which has low density, good mechanical property and similar shrinkage rate to ABS is obtained.

Preferably, the melt flow rate of the PP resin at 230 ℃ and 2.16kg is 8-50 g/10 min.

More preferably, the melt flow rate of the PP resin at 230 ℃ and 2.16kg is 28-40 g/10 min.

Preferably, the melt flow rate of the POE resin at 190 ℃ and 2.16kg is 2-30 g/10 min.

More preferably, the melt flow rate of the POE resin at 190 ℃ and 2.16kg is 5-18 g/10 min.

The melt flow rate was measured according to ISO 1133-1-2011 standard method.

Preferably, the whisker is one or more of magnesium sulfate whisker, calcium sulfate whisker or barium sulfate whisker.

Preferably, the diameter of the whisker is less than or equal to 4 mu m, and the length-diameter ratio is more than or equal to 20.

Within the above diameter and length ranges, the whiskers have a larger aspect ratio, contributing to a more pronounced improvement in the stiffness of the material at smaller addition levels.

Preferably, the foaming agent masterbatch comprises a carrier resin, a chemical foaming agent and a foaming active agent.

More preferably, in the foaming agent master batch, the carrier resin accounts for 23-40 wt.%, the chemical foaming agent accounts for 57-75 wt.%, and the foaming active agent accounts for 2-3 wt.%.

During the foaming process, the foaming active agent helps to reduce the surface tension of the system and generate more foaming foams, so that the foaming performance of the material is better.

Preferably, the carrier resin is a polypropylene resin.

The carrier resin is cooperated with the resin matrix of the spray-free polypropylene composition, which is beneficial to more uniform dispersion of the foaming agent master batch.

Preferably, the chemical blowing agent is an azo-based blowing agent.

Optionally, the azo foaming agent is one or more of azodicarbonamide, azodiisoheptanonitrile or azodiisobutyronitrile.

Preferably, the foaming active agent is zinc oxide and/or magnesium oxide.

Preferably, the metallic effect pigment is aluminum powder.

More preferably, the D50 particle size of the aluminum powder is 10-100 μm.

Preferably, the compatibilizer is maleic anhydride grafted polypropylene.

The invention also provides a preparation method of the spray-free polypropylene composition, which comprises the following steps:

and mixing PP resin, POE resin, whiskers, a compatilizer, a metal effect pigment and foaming agent master batches, adding the mixture into an extruder, and performing melt mixing, extrusion and granulation to obtain the spray-free polypropylene composition.

Preferably, the extruder is a twin screw extruder.

Preferably, the extrusion temperature of the double-screw extruder is 190-220 ℃, and the screw rotating speed is 450-550 rpm.

The invention also protects the application of the spray-free polypropylene composition in automobile interior and exterior materials.

The spraying-free polypropylene composition has the shrinkage rate close to that of an ABS material, and can be directly used for injection molding and mold opening of the ABS material by using a mold.

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

the invention develops a spraying-free polypropylene composition with low density and good mechanical property, and a preparation method and application thereof. By introducing POE resin and crystal whiskers, the rigidity and toughness of the polypropylene material are synchronously improved, and the shrinkage rate of the prepared spray-free polypropylene composition is similar to that of an ABS material. The addition of the metal effect pigment enables the polypropylene material to have the spraying-free metal effect and keep low density; the foam master batch further reduces the density of the material in the spray-free polypropylene composition.

Detailed Description

The present invention will be further described with reference to the following embodiments.

The raw materials in the examples and comparative examples are commercially available;

reagents, methods and apparatus used in the present invention are conventional in the art unless otherwise indicated.

Examples 1 to 16

Examples 1 to 16 respectively provide a spray-free polypropylene composition, the component contents of which are shown in table 1, and the preparation method is as follows:

mixing the components according to the table 1, adding the mixture into a double-screw extruder, and performing melt mixing and extrusion granulation to obtain a spray-free polypropylene composition; wherein the extrusion temperature of the double-screw extruder is 190-220 ℃, and the screw rotating speed is 450-550 rpm.

TABLE 1 component content (parts by weight) of the spray-free polypropylene compositions of examples 1 to 16

Comparative examples 1 to 5

Comparative examples 1 to 5 respectively provide a spray-free polypropylene composition, the component contents of which are shown in Table 2, and the preparation method comprises the following steps:

mixing the components according to the table 2, adding the mixture into a double-screw extruder, and performing melt mixing and extrusion granulation to obtain a spray-free polypropylene composition; wherein the extrusion temperature of the double-screw extruder is 190-220 ℃, and the screw rotating speed is 450-550 rpm.

TABLE 2 component contents (parts by weight) of the spray-free polypropylene compositions of comparative examples 1 to 5

		1	2	3	4	5
							PP resin	PP-1	60	60	60	60	60
POE resin	POE-1	-	10	10	10	10
							Whisker	Whisker-1	20	5	30	20	20
Compatilizer	/	2	2	2	2	-
							Metal effect pigments	Aluminum powder-1	3	3	3	3	3
Foaming agent master batch	Foaming agent master batch-1	2	2	2	-	2

Performance test

The performance test of the spray-free polypropylene compositions prepared in the above examples and comparative examples was carried out by the following specific methods:

density: testing by using a densitometer according to method A in GB 1033-1-2008;

shrinkage rate: the test was carried out according to the method of GBT 15585-1995, wherein the mold dimensions used were 219.9mm in length and 49.74mm in width;

notched izod impact strength: testing according to a GB/T1043-2008 standard method, wherein the specification of a sample is 80mm multiplied by 10mm multiplied by 4mm, the type of a notch is A type, and the notch is machined;

flexural modulus: the test speed is 2mm/min and the specification of the sample is 80mm multiplied by 10mm multiplied by 4mm according to the test method of GB/T9341-2008 standard.

The test results of the examples and comparative examples are shown in Table 3.

TABLE 3 test results of examples and comparative examples

From the test results in table 3, the shrinkage rate of the spray-free polypropylene compositions prepared in examples 1 to 16 is close to that of the electroplated ABS material, and the shrinkage rate difference from that of the electroplated ABS material is less than or equal to 0.06%. The mechanical property of the spray-free polypropylene composition prepared by the embodiment is equivalent to that of an electroplating ABS material, and the density of the spray-free polypropylene composition is far lower than that of the electroplating ABS material, namely the spray-free polypropylene composition can reduce the material density on the basis of keeping high mechanical property, and is beneficial to the development of light weight of automobiles.

In examples 1 to 4, it can be seen that the material mechanical properties are better along with the reduction of the melt flow rate of the PP resin, but when the melt flow rate of the PP resin is too low or too high, the difference between the shrinkage rate of the spray-free polypropylene composition and the plated ABS material becomes larger. Considering that the mechanical properties of the spray-free polypropylene compositions of examples 1 to 4 all meet the mechanical requirements of practical use, and the shrinkage rate has a more significant effect on the injection molding effect of the material, the melt flow rate of the polypropylene resin at 230 ℃ and 2.16kg is preferably 28 to 40g/10 min.

According to the embodiments 1 and 5 to 7, when the melt flow rate of the POE resin is 5 to 18g/10min at 190 ℃ under the condition of 2.16kg, the shrinkage rate of the spray-free polypropylene composition is closer to that of the electroplating ABS material.

The shrinkage rates of the spray-free polypropylene compositions prepared in examples 1, 10 and 11 are close, wherein the carrier of the foaming agent master batch used in example 8 is polypropylene, the chemical foaming agent is azodicarbonamide, and the spray-free polypropylene composition prepared in example 8 has lower density and better mechanical properties. Therefore, it is preferable that the carrier resin is a polypropylene resin; preferably, the chemical blowing agent is an azo-based blowing agent.

From the test results of example 1 and examples 14 to 16, it can be seen that the mass ratio of POE to whisker has a significant effect on the shrinkage of the prepared spray-free polypropylene composition. And when the mass ratio of the POE resin to the crystal whisker is 1: (1.5-2), the shrinkage rate of the spray-free polypropylene composition is closer to that of the ABS material.

Compared with the prior art, the material does not contain POE, and has lower impact strength of a cantilever notch and poor toughness; in comparative example 2, the whisker content was too small, and the rigidity of the material was poor. And because POE or whisker is not contained, the shrinkage rate of the spraying-free polypropylene composition can not be adjusted by the synergistic effect of POE resin and the whisker, the shrinkage rate of the spraying-free polypropylene compositions prepared in comparative examples 1 and 2 is too large compared with that of an electroplating ABS material, and the die opening and injection molding of the spraying-free polypropylene compositions by using an ABS die are difficult.

In comparative example 3, the content of whiskers was too high, and although the rigidity of the prepared spray-free polypropylene composition was excellent, the toughness was poor, the density was too high, and the material shrinkage was very low due to too much content of whiskers, which was not matched with a mold for an ABS material.

Comparative example 4 contains no blowing agent and the spray-free polypropylene composition has too high a density. Comparative example 5 does not contain a compatibilizer, and the whiskers have poor bonding force with the polypropylene resin and the POE resin, so that the rigidity of the material cannot be effectively increased, and the material is too hard and brittle and has poor toughness.

It should be understood that the above-described embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. Other variations and modifications will be apparent to persons skilled in the art in light of the above description. And are neither required nor exhaustive of all embodiments. Any modification, equivalent replacement, and improvement made within the spirit and principle of the present invention should be included in the protection scope of the claims of the present invention.

Claims

1. The spraying-free polypropylene composition with low density and good mechanical property is characterized by comprising the following components in parts by weight:

50-70 parts of PP resin,

8-16 parts of POE resin,

1-3 parts of a compatilizer,

2-5 parts of a metal effect pigment,

1-3 parts of foaming agent master batch.

2. The spray-free polypropylene composition according to claim 1, wherein the PP resin has a melt flow rate of 8 to 50g/10min at 230 ℃ and 2.16 kg.

3. The spray-free polypropylene composition of claim 1, wherein the POE resin has a melt flow rate of 2-30 g/10min at 190 ℃ under 2.16 kg.

4. The spray-free polypropylene composition according to claim 1, wherein the whiskers are one or more of magnesium sulfate whiskers, calcium sulfate whiskers or barium sulfate whiskers.

5. The spray-free polypropylene composition according to claim 1, wherein the diameter of the whisker is not more than 4 μm, and the length-diameter ratio is not less than 20.

6. The spray-free polypropylene composition according to claim 1, wherein the mass ratio of the POE resin to the whiskers is 1: (1.5-2).

7. The spray-free polypropylene composition according to claim 1, wherein the foaming agent masterbatch comprises a carrier resin, a chemical foaming agent and a foaming activator; the carrier resin is polypropylene, the chemical foaming agent is an azo foaming agent, and the foaming active agent is zinc oxide and/or magnesium oxide.

8. The spray-free polypropylene composition according to claim 1, wherein the metal effect pigment is aluminum powder, and the D50 particle size is 10-100 μm.

9. The preparation method of the spray-free polypropylene composition according to any one of claims 1 to 8, comprising the steps of:

10. Use of the spray-free polypropylene composition according to any one of claims 1 to 8 in automotive interior and exterior materials.