CN112063042A - Degradable polypropylene plastic and preparation method and application thereof - Google Patents

Abstract

The application discloses degradable polypropylene plastic and a preparation method and application thereof, and relates to the field of polypropylene plastic, wherein the degradable polypropylene plastic is prepared from the following raw materials in parts by weight: 35-60 parts of polypropylene, 1-5 parts of ethylene propylene diene monomer, 5-15 parts of glass fiber, 1-5 parts of vermiculite, 15-20 parts of calcium silicate, 1-5 parts of dibutyl phthalate and 10-15 parts of a degrading agent, wherein the degrading agent is cellulose coated by activated carbon. The polypropylene plastic can be applied to a packaging cover, has degradability, can be applied to a humid environment, and reduces the possibility that the degradation agent absorbs water in polypropylene to change the property of the polypropylene.

Description

Degradable polypropylene plastic and preparation method and application thereof

Technical Field

The application relates to the field of polypropylene plastics, in particular to degradable polypropylene plastics and a preparation method and application thereof.

Background

The polypropylene plastic is a semi-crystalline thermoplastic plastic, has high impact resistance, high mechanical property and toughness, resists corrosion of various organic solvents and acid and alkali, is widely applied in the industry, and is one of common high polymer materials. After the traditional polypropylene plastic product enters the environment, the long-term and deep ecological environment problem is caused because the traditional polypropylene plastic product is difficult to degrade.

At present, the degradable plastics of polypropylene series, including adding the degradable material in traditional petroleum-based plastics, after the degradable material added in polypropylene plastics degrades, the plastic products are decomposed into smaller petroleum-based plastic fragments, thereby reducing the fatal risk of organisms because of eating by mistake or being wound, and being convenient for subsequent treatment. Cellulose is a substance existing in a large amount in nature, at present, the cellulose is often used as a degradable additive to be added into polypropylene plastic, and after the polypropylene plastic is discarded, the cellulose is degraded from the surface to the inside to destroy the integral structure of the polypropylene plastic, so that the polypropylene plastic becomes polypropylene fragments.

However, due to the physical and chemical properties of cellulose, there are still some drawbacks when cellulose is added as a degradable aid for polypropylene plastics. When cellulose is used as an additive for polypropylene plastics, the use of polypropylene plastics is limited.

Disclosure of Invention

In view of the problems of the prior art, a first object of the present application is to provide a degradable polypropylene plastic which can be used in a humid environment and can also contain liquid.

The second purpose of the present application is to provide a preparation method of degradable polypropylene plastic, and the degradable polypropylene plastic prepared by the preparation method has the advantage of stable performance in a humid environment.

A third object of the present application is to provide a use of a degradable polypropylene plastic, wherein the degradable polypropylene plastic has a property that is not easily changed in a humid environment, and can be applied to a packaging cover, so that the packaging cover can be applied to the humid environment or the possibility of water absorption and denaturation when the packaging cover is used for packaging liquid is reduced.

In order to achieve the first object, the present application provides the following technical solutions: a degradable polypropylene plastic comprises the following raw materials in parts by weight: 35-60 parts of polypropylene, 1-5 parts of ethylene propylene diene monomer, 5-15 parts of glass fiber, 1-5 parts of vermiculite, 15-20 parts of calcium silicate, 1-5 parts of dibutyl phthalate and 10-15 parts of a degrading agent, wherein the degrading agent is cellulose coated by activated carbon.

Through adopting above-mentioned technical scheme, polypropylene plastics destroys polypropylene plastics's structure through the method of degradation cellulose after the abandonment, reduce the degree of difficulty that polypropylene plastics was handled, polypropylene plastics product is when normal use, the active carbon of cellulose skin parcel reduces the possibility of cellulose with the direct contact of moisture, reduce the possibility that cellulose absorbs water swelling, reduce because the cellulose absorbs water swelling leads to the possibility that polypropylene plastics performance changes, and the microporous structure of active carbon provides the passageway of microorganism contact cellulose, increase the possibility of microorganism degradation cellulose.

Further, the activated carbon is hydrophobic activated carbon, and the specific method for coating cellulose with hydrophobic activated carbon comprises the following steps:

mixing an adhesive, an accelerant and cellulose, uniformly stirring, spraying the cellulose with the adhesive and the accelerant adhered to the outer layer into hydrophobic activated carbon, oscillating, drying and screening to obtain the cellulose with the hydrophobic activated carbon coated on the outer layer.

By adopting the technical scheme, the hydrophobic activated carbon improves the water-resisting effect of the activated carbon, the hydrophobic activated carbon is tightly wrapped on the outer layer of the cellulose through the bonding effect of the adhesive, the accelerator promotes the curing of the adhesive, and the possibility that the hydrophobic activated carbon falls off in the processing process is reduced.

Furthermore, the preparation raw materials of each part of the degradation agent comprise 15-20 parts of hydrophobic activated carbon, 10-15 parts of adhesive, 0.5-1 part of accelerator and 20-30 parts of cellulose.

Through adopting above-mentioned technical scheme, hydrophobic type active carbon wraps up in the periphery of cellulose under the effect of gluing agent, and hydrophobic type active carbon quantity undersize can't closely wrap up the cellulose, and hydrophobic type active carbon quantity is too much can't adhere in the cellulose skin, causes the waste. The using amount of the adhesive is too small to adhere to the hydrophobic activated carbon, the hydrophobic activated carbon with the too large using amount of the adhesive is coated by the adhesive, and the accelerator promotes the adhesive to be dried at a proper speed, so that the possibility of drying the adhesive when the adhesive is too slow and the activated carbon is not coated is reduced.

Further, the adhesive is epoxy resin or rosin resin.

By adopting the technical scheme, the adhesive can be decomposed, and the possibility that the adhesive influences the degradation of cellulose is reduced.

Further, before mixing the adhesive, the accelerator and the cellulose, the cellulose is prepared into an agglomerate in advance, and the specific method for preparing the agglomerate comprises the following steps:

adding a binder into the cellulose, uniformly stirring to form an agglomerate of the cellulose and the binder, and grinding the agglomerate to a particle size of 400-500 mu m after drying.

Further, before spraying the cellulose with the adhesive and the accelerant adhered to the outer layer to the hydrophobic activated carbon, the hydrophobic activated carbon is pre-ground to be 40-50 μm in particle size.

Through adopting above-mentioned technical scheme, before mixing gluing agent, promoter and cellulose, the particle size of control reunion thing, before hydrophobic type active carbon cladding cellulose, the particle size of control hydrophobic type active carbon makes the particle size of reunion thing great and hydrophobic type active carbon less, and the hydrophobic type active carbon of being convenient for wraps up in the reunion thing periphery compactly, reduces the gap between the adjacent hydrophobic type active carbon, reduces the cellulose in the reunion thing and absorbs water the swelling's possibility through the gap between the hydrophobic type active carbon.

Further, the specific conditions of the injection are: the spraying speed is controlled at 10-15 m/s.

By adopting the technical scheme, redundant adhesive on the surface of the agglomerate is peeled off by air in the injection process, the thickness of the adhesive is controlled to be 20-30 mu m, the thickness of the adhesive is smaller than the particle size of the hydrophobic activated carbon, one part of the hydrophobic activated carbon is bonded with the adhesive, and the other part of the hydrophobic activated carbon is exposed outside, so that the probability that the hydrophobic activated carbon is coated by the adhesive is reduced, and microorganisms can contact cellulose through micropores of the hydrophobic activated carbon from the outside.

In order to achieve the second object, the present application provides the following technical solutions:

a preparation method of degradable polypropylene plastic comprises the following steps:

(1) preparing a degradation agent, and uniformly mixing the degradation agent with other raw materials to obtain a mixture;

(2) the mixture is sent to a feeding part, the rotating speed of an extrusion screw is 450-; the temperature of the C5 section at the natural exhaust position is 170-210 ℃; the temperature of the C6 section at the side feeding part is 170-210 ℃, the temperature of the C7 section is 190-230 ℃, and the temperature of the C8 section is 190-230 ℃; the temperature of the C9 section at the vacuum exhaust position is 190-230 ℃, and the temperature of the C10 section is 190-230 ℃; the temperature at the head is 190-230 ℃;

(3) extruding, water cooling, granulating, and placing in an environment of 190-230 ℃ for heat preservation for 2-3 hours to obtain the degradable polypropylene plastic.

By adopting the technical scheme, the degradable polypropylene plastic is obtained by blending the cellulose with the hydrophobic activated carbon wrapped on the outer layer and other raw materials of the polypropylene plastic.

In order to achieve the third object, the present application provides the following technical solutions: the degradable polypropylene-based plastic is used for preparing a packaging cover.

In summary, the present application has the following beneficial effects:

1. this application adopts the cellulose of active carbon parcel to add polypropylene plastics as the additive in, the micropore and the external intercommunication of active carbon, the micropore contact cellulose of microorganism accessible active carbon, decomposition cellulose, and active carbon separation cellulose and external environment direct contact reduce the possibility of moisture in the cellulose absorption environment, reduce the cellulose and absorb water swelling and destroy polypropylene plastics physical properties's possibility.

2. The cellulose and the adhesive are mixed, the agglomerates are firstly ground into particles with the particle size of 400-500 mu m, then the hydrophobic activated carbon is ground to the particle size of 40-50 mu m, the particle size difference between the agglomerates and the hydrophobic activated carbon is large, the hydrophobic activated carbon is conveniently and compactly wrapped on the periphery of the agglomerates, gaps between adjacent hydrophobic activated carbons are reduced, and the possibility of water absorption and swelling of the cellulose in the agglomerates is reduced.

3. According to the preparation method, the epoxy resin or the rosin resin is used as the adhesive, the bonding capacity of the epoxy resin and the rosin resin is good, the bonding force of the hydrophobic activated carbon and the cellulose is enhanced, and the possibility that the hydrophobic activated carbon falls off from the surface of the cellulose is reduced; the resin is a degradable substance, and the resin is coated on the periphery of the cellulose as an adhesive, so that the influence on the degradation of the cellulose is reduced.

Detailed Description

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

Examples of preparation of raw materials

Preparation example 1: in the present preparation example, each degradation agent was prepared from the raw materials having the particle sizes shown in table 1 and the weight parts shown in table 2. The mode of preparing the degradation agent is as follows:

adding epoxy resin as adhesive into cellulose, stirring to form cellulose and epoxy resin agglomerate, drying naturally and ball milling to obtain agglomerate with large grain size for the active carbon to pack the cellulose compactly. Mixing epoxy resin serving as an adhesive, cobalt naphthenate serving as an accelerant and particles of agglomerates, uniformly stirring, spraying the agglomerates with the adhesive and the accelerant adhered to the outer layer into hydrophobic activated carbon, vibrating, stirring, drying, slightly shaking to remove the activated carbon which is not combined with the adhesive, and screening by using a screen with the mesh number of 100, wherein a degrading agent is arranged on the screen, and the substances below the screen are the hydrophobic activated carbon which can be recycled.

Preparation examples 2 to 7

A degradation agent, which is different from example 1 in that it was prepared from raw materials containing the particle size shown in table 1 and the weight shown in table 2.

TABLE 1 particle size of raw materials in preparation examples 1 to 7

TABLE 2 raw materials and weights in preparation examples 1 to 7

Preparation example 8

A degradation agent, which is different from comparative example 2 in that the cellulose-coated activated carbon is a normal activated carbon.

Taking 5cm³The degradation agents prepared in preparation examples 1 to 8 were immersed in water at normal temperature for 8 hours and then taken out to measure the volume.

TABLE 3 volume of degradant soaked in preparations 1-8

Preparation example	Volume of degradant (cm)3)
		Preparation example 1	5.16
Preparation example 2	5.24
		Preparation example 3	5.08
Preparation example 4	5.12
		Preparation example 5	5.03
Preparation example 6	5.18
		Preparation example 7	32.31
Preparation example 8	21.09

Test results and analysis: it can be seen from the combination of preparation examples 1 to 8 and table 3 that the degradation agent volume of preparation examples 1 to 6 is not significantly increased, and the degradation agent volume of preparation example 7 is increased, so that the degradation agent prepared by coating the hydrophobic activated carbon outside the agglomerate has a reduced possibility of absorbing water and hardly absorbs water from the surrounding environment, compared with the degradation agent prepared by not coating the hydrophobic activated carbon outside the agglomerate, and the volume of preparation example 8 is larger than that of preparation examples 1 to 6 and smaller than that of preparation example 7, so that the cellulose outer layer is coated with the ordinary activated carbon, although the absorption of water by cellulose can be reduced, the cellulose outer layer still has the defect of absorbing water.

Examples

The following examples used the degradation agent prepared in preparation example 2.

Example 1

A degradable polypropylene plastic is prepared from raw materials with the weight shown in Table 4, and the preparation method comprises the following steps:

(1) uniformly mixing the degradation agent prepared in the preparation example 2 with other raw materials to obtain a mixture;

(2) extruding the mixture, wherein the rotating speed of an extrusion screw is 450 r/min, the temperature of a C1 section at a main feeding position is 190 ℃, the temperature of a C2 section is 230 ℃, the temperature of a C3 section is 230 ℃, and the temperature of a C4 section is 230 ℃; the temperature of C5 section at the natural exhaust is 170 ℃; the temperature of the C6 section at the side feeding part is 170 ℃, the temperature of the C7 section is 190 ℃, and the temperature of the C8 section is 190 ℃; the temperature of the C9 section at the vacuum exhaust position is 190 ℃, and the temperature of the C10 section is 190 ℃; the temperature at the nose is 190 ℃;

(3) extruding, water cooling, granulating, and preserving heat for 2 hours in an environment of 190 ℃ to obtain the degradable polypropylene plastic.

Examples 2 to 5: a degradable polypropylene plastic is different from the degradable polypropylene plastic in example 1 in that the raw materials and the weight of the degradable polypropylene plastic are shown in Table 3 in examples 2 to 5.

TABLE 4 raw materials and weights in examples 1-5

Example 6

A degradable polypropylene plastic is different from the degradable polypropylene plastic in example 5 in that the specific preparation method comprises the following steps:

(1) uniformly mixing the degradation agent prepared in the preparation example 2 with other raw materials to obtain a mixture;

(2) extruding the mixture, wherein the rotating speed of an extrusion screw is 650 r/min, the temperature of a C1 section at the main feeding position is 230 ℃, the temperature of a C2 section is 270 ℃, the temperature of a C3 section is 270 ℃, and the temperature of a C4 section is 270 ℃; the temperature of C5 section at the natural exhaust is 210 ℃; the temperature of the C6 section at the side feeding part is 210 ℃, the temperature of the C7 section is 230 ℃, and the temperature of the C8 section is 230 ℃; the temperature of the C9 section at the vacuum exhaust position is 230 ℃, and the temperature of the C10 section is 230 ℃; the temperature at the nose is 230 ℃;

(3) extruding, water cooling, granulating, and preserving heat for 3 hours in an environment of 230 ℃ to obtain the degradable polypropylene plastic.

Comparative example

The following comparative examples used the degradation agent prepared in preparation example 2.

Comparative examples 1 to 2: a degradable polypropylene plastic is prepared from the raw materials and the weight shown in the table 5.

TABLE 5 raw materials and weights in comparative examples 1-2

Comparative example 3

A degradable polypropylene plastic, which is different from comparative example 2 in that the degradation agent of comparative example 2 is not coated with activated carbon.

Comparative example 4

A degradable polypropylene plastic is different from that of comparative example 2 in that the coating material of the degradation agent of comparative example 2 is common activated carbon.

Performance test

1. The tensile test method comprises the following steps: the degradable polypropylene plastics obtained in each example and comparative example were prepared into round plastic sheet samples with a thickness of 1mm and a radius of 5cm, and after the round plastic sheets were immersed in water for 8 hours, tensile tests were performed at a rate of 50mm/min using a TENSILON 200 tester to obtain data on breaking strength and breaking elongation.

2. Degradation test method: the degradable polypropylene plastics obtained in each example and comparative example were prepared into a round plastic sheet sample having a thickness of 1mm and a radius of 5cm, the round plastic sheet sample was stored in a compost environment at a temperature controlled at 60 ℃ for 80 days, and the form of the round plastic sheet sample was observed.

TABLE 6 breaking Strength and elongation at Break of examples 1-6 and comparative examples 1-4

Tensile test	Breaking Strength (MPa)	Elongation at Break (%)
			Example 1	0.71	1201
Example 2	0.74	1275
			Example 3	0.73	1185
Example 4	0.71	1293
			Example 5	0.75	1199
Example 6	0.78	1165
			Comparative example 1	0.73	1279
Comparative example 2	0.60	967
			Comparative example 3	0.12	285
Comparative example 4	0.33	469

TABLE 7 degradation degree of examples 1-6 and comparative examples 1-4

As can be seen by combining examples 1-6 with comparative examples 1-4 and by combining Table 6, the breaking lengths and breaking elongations of examples 1-6 are close to each other and greater than those of comparative examples 1-4, and therefore it is presumed that the tensile strengths of the polypropylene plastic samples of examples 1-6 are greater.

As can be seen from comparative examples 1 to 4 in combination with Table 6, the breaking length and breaking elongation of examples 1 to 2 are close to each other and larger than those of comparative examples 3 to 4, and therefore it is presumed that the tensile strength of the polypropylene plastic samples of comparative examples 1 to 2 is larger. The breaking length and the breaking elongation of the comparative example 4 are larger than those of the comparative example 3 and smaller than those of the comparative examples 1-2, so that the cellulose outer layer is coated with the common activated carbon, and the water absorption and denaturation degree of the degradation agent is smaller than that of the degradation agent which is not coated with the activated carbon and is larger than that of the degradation agent which is coated with the hydrophobic activated carbon.

According to the tensile strengths of examples 1 to 6 and comparative examples 1 to 4, it is assumed that the tensile strength of the polypropylene plastic sample is better when the addition amount of the degradation agent is less than a certain amount, the tensile strength of the polypropylene plastic sample is reduced when the addition amount of the degradation agent is more than a certain amount, and the tensile strength of the degradable polypropylene plastic after being soaked in water for 8 hours is better when the outer layer of the degradation agent is coated with the hydrophobic activated carbon. When the outer layer of the degradation agent is not coated with the hydrophobic activated carbon, the degradable polypropylene plastic has poor stretching after being soaked in water for 8 hours. When the outer layer of the degradation agent is coated with the common activated carbon, the degradable polypropylene plastic is better than the degradation agent which is not coated with the activated carbon and is worse than the degradation agent coated with the hydrophobic activated carbon after being soaked in water for 8 hours.

According to examples 1 to 6, comparative examples 1 to 4 and Table 7, it can be seen that when the amount of the degradation agent added is 10 to 15kg, the degradation agent can be degraded and the polypropylene plastic can be broken into small pieces after 80 days of composting treatment regardless of whether the outer layer is coated with or not, and regardless of whether the outer layer is made of ordinary activated carbon or hydrophobic activated carbon. When the additive is less than 10kg, the polypropylene plastic is perforated on the surface after 80 days of composting treatment, but the integral form is kept unchanged, and the polypropylene plastic is not successfully broken into fragments.

According to examples 1 to 6, comparative examples 1 to 4, tables 6 and 7, it is understood that the addition of the degradation agent to the polypropylene plastic can destroy the polypropylene plastic regardless of the presence or absence of the coated activated carbon in the outer layer, and regardless of whether the activated carbon is a normal activated carbon or a hydrophobic activated carbon, and that the destruction effect is good when the addition amount is 10kg or more, but the tensile strength of the polypropylene plastic is reduced when the addition amount of the degradation agent to coat the activated carbon is more than 15 kg. If the degradation agent added into the polypropylene plastic is not coated by the active carbon, the degradation of the polypropylene plastic is not influenced, but the degradation agent cannot be applied to a humid environment, and the use of the polypropylene plastic is limited.

The present embodiment is only for explaining the present application, and it is not limited to the present application, 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 application.

Claims (9)

1. The degradable polypropylene plastic is characterized by being prepared from the following raw materials in parts by weight:

35-60 parts of polypropylene;

1-5 parts of ethylene propylene diene monomer;

5-15 parts of glass fiber;

1-5 parts of vermiculite;

15-20 parts of calcium silicate;

1-5 parts of dibutyl phthalate;

10-15 parts of a degradation agent;

the degradation agent is cellulose coated by active carbon.

2. A degradable polypropylene plastic according to claim 1, wherein the activated carbon is hydrophobic activated carbon, and the specific method for coating cellulose with the hydrophobic activated carbon comprises the following steps:

mixing an adhesive, an accelerant and cellulose, uniformly stirring, spraying the cellulose with the adhesive and the accelerant adhered to the outer layer into hydrophobic activated carbon, oscillating, drying and screening to obtain the cellulose with the hydrophobic activated carbon coated on the outer layer.

3. A degradable polypropylene plastic according to claim 2, wherein raw materials for preparing each part of the degradation agent comprise 15-20 parts of hydrophobic activated carbon, 10-15 parts of adhesive, 0.5-1 part of accelerator and 20-30 parts of cellulose.

4. A degradable polypropylene plastic according to claim 2, wherein the adhesive is epoxy resin or rosin resin.

5. A degradable polypropylene plastic according to claim 2, wherein the cellulose is prepared into agglomerates in advance before the adhesive, the accelerator and the cellulose are mixed, and the method for preparing the agglomerates comprises the following steps:

adding a binder into cellulose, uniformly stirring to form an agglomerate of the cellulose and the binder, drying, and grinding the agglomerate to a particle size of 400-500-μm。

6. A degradable polypropylene plastic according to claim 5, wherein the hydrophobic activated carbon is pre-ground to a particle size of 40-50 before spraying the cellulose with the adhesive and the accelerator adhered to the outer layer onto the hydrophobic activated carbonμ m。

7. A degradable polypropylene plastic according to claim 6, wherein the specific conditions of spraying are as follows: the spraying speed is controlled at 10-15 m/s.

8. A method for preparing a degradable polypropylene plastic according to any one of claims 1 to 7, comprising the steps of:

(1) preparing a degradation agent, and uniformly mixing the degradation agent with other raw materials to obtain a mixture;

(2) the mixture is sent to a feeding part, the rotating speed of an extrusion screw is 450-; the temperature of the C5 section at the natural exhaust position is 170-210 ℃; the temperature of the C6 section at the side feeding part is 170-210 ℃, the temperature of the C7 section is 190-230 ℃, and the temperature of the C8 section is 190-230 ℃; the temperature of the C9 section at the vacuum exhaust position is 190-230 ℃, and the temperature of the C10 section is 190-230 ℃; the temperature at the head is 190-230 ℃;

(3) extruding, water cooling, granulating, and placing in an environment of 190-230 ℃ for heat preservation for 2-3 hours to obtain the degradable polypropylene plastic.

9. Use of a degradable polypropylene plastic according to any one of claims 1 to 7 for the manufacture of packaging closures.