CN116814159A

CN116814159A - Emulsion applied to PP material and preparation method thereof

Info

Publication number: CN116814159A
Application number: CN202310896897.XA
Authority: CN
Inventors: 陈云; 李军
Original assignee: Guangdong Jinyi Technology Co ltd
Current assignee: Guangdong Jinyi Technology Co ltd
Priority date: 2023-07-20
Filing date: 2023-07-20
Publication date: 2023-09-29

Abstract

The application relates to the technical field related to paint preparation, and particularly discloses an emulsion applied to a PP material and a preparation method thereof, wherein the emulsion applied to the PP material is prepared from the following raw materials, by weight, 14-20 parts of polysilazane resin, 3-7 parts of chlorinated polyolefin, 0.3-0.7 part of an additive and 6-9 parts of a solvent; the chlorine content of the polyolefin is below 50%; the additive is one or two selected from carboxymethyl cellulose and casein glue. The emulsion applied to the PP material has the effects of high adhesive force and high crack resistance, and the preparation method is simple and convenient for mass production.

Description

Emulsion applied to PP material and preparation method thereof

Technical Field

The application relates to the technical field related to paint preparation, in particular to an emulsion applied to a PP material and a preparation method thereof.

Background

At present, polypropylene (PP) is used as one of general plastics and is widely applied to various fields of chemical industry, medical treatment, machinery, transportation and the like; in order to improve the appearance quality of the PP device and prolong the service life of the PP device, so as to improve the competitiveness of the PP device in the market, the development of the paint for PP plastic is very important.

However, the PP material has low surface energy, high crystallinity and very low polarity, so that the paint is difficult to have good adhesive force on the surface; particularly, under the low temperature condition, the adhesion force of the surface of the PP base material is further reduced due to the fact that the crystal grains of many PP materials (such as coamings used in a refrigerator) are large, the rigidity and the toughness are increased at the low temperature, so that the conventional surface treatment methods such as flame treatment, plasma treatment, corona treatment and the like are difficult to increase, the processes of the methods are complex, the effect of the surface treatment is uneven, the activation aging is short, the deformation of complex parts is easy to cause, the investment cost is increased, and on the other hand, even after the coating is applied to the surface of the PP base material through the surface treatment, the surface of the coating is easy to store water and condense under the low temperature and humidity condition, the internal brittleness of the coating is increased, and the cracking resistance is poor at the low temperature.

Therefore, there is a need to propose an emulsion suitable for high adhesion, high crack resistance at low temperature, capable of being stably applied to the surface of PP materials.

Disclosure of Invention

In order to improve the adhesive force and the crack resistance of the PP material emulsion under the condition of low temperature regulation, the application provides an emulsion applied to the PP material and a preparation method thereof.

The first object of the application is to provide an emulsion applied to a PP material, the second object of the application is to provide a method for preparing an emulsion applied to a PP material, and the third object of the application is to provide an application of an emulsion applied to a PP material.

The application provides an emulsion applied to a PP material, which adopts the following technical scheme:

an emulsion applied to PP materials is prepared from the following raw materials in parts by weight:

14-20 parts of polysilazane resin,

3-7 parts of chlorinated polyolefin,

0.3 to 0.7 part of additive,

6-9 parts of a solvent;

the chlorine content of the chlorinated polyolefin is below 50%; the additive is one or two selected from carboxymethyl cellulose and casein glue.

By adopting the technical scheme, the emulsion prepared from the polysilazane resin, the chlorinated polyolefin with the chlorine content lower than 50wt% and the carboxymethyl cellulose is used, when the emulsion is coated on a PP material, the coating has high adhesive force and good hydrophobicity, the test piece after low-temperature and alkali treatment can reach the elongation of more than 370, and peeling do not occur in a low-temperature freeze thawing cycle test, which is probably because the polysilazane resin has low surface energy and better fatigue resistance as a resin matrix, and can change the property of the polysilazane resin and improve the moist heat resistance and weather resistance under the action of adding the chlorinated polyolefin and the carboxymethyl cellulose.

Optionally, the additive consists of carboxymethyl cellulose and casein glue in the mass ratio of (0.25-0.4) to 1.

Preferably, the additive consists of carboxymethyl cellulose and casein glue according to the mass ratio of 0.3:0.2.

By adopting the technical scheme, compared with the single addition, after the carboxymethyl cellulose and the casein glue are mixed and added, the water contact angle of the prepared emulsion is obviously increased, the hydrophobic property is improved, the anti-cracking elongation is obviously improved, and the improvement of the anti-cracking elongation and the hydrophobic property has a synergistic effect.

Optionally, the mass ratio of the lithium chloride to the solvent is 1 (6.7-14.4);

preferably, the solvent is selected from one of dimethylacetamide and dimethylformamide;

preferably, the solvent is dimethylacetamide.

By adopting the technical scheme, after the lithium chloride is added, the stripping grade of the coating is reduced, the adhesive force of the emulsion is improved, the hydrophobicity is increased, the low-temperature anti-cracking elongation and the alkali treatment anti-cracking elongation are both improved, which is probably because after the lithium chloride is added, the compatibility between the chlorinated polyolefin and polysilazane resin and additives can be promoted, the emulsion dispersion is enhanced, and the polysilazane resin has a number average molecular weight of 750-1000.

Preferably, the polysilazane resin has a number average molecular weight of 800 to 900.

Optionally, the chlorinated polyolefin has a chlorine content of 15 to 22wt%.

By adopting the technical scheme, the number average molecular weight of the polysilazane resin has influence on the crack elongation and the water contact angle of the emulsion, the stripping grade reaches 0 grade when the chlorine content of chlorinated polyolefin is preferably 15-22wt%, the adhesive force is higher, the surface of the emulsion coating reaches the super-hydrophobic grade, and the phenomena of water drop adhesion and condensation in a low-temperature and humid environment are reduced.

Optionally, the degree of substitution of the carboxymethyl cellulose is 0.4-1.5.

Preferably, the degree of substitution of the carboxymethyl cellulose is 0.7.

Optionally, the carboxymethyl cellulose has an average particle size of less than 100 μm.

Preferably, the carboxymethyl cellulose has an average particle size of 45-55 μm.

Preferably, the carboxymethyl cellulose has an average particle size of 50 μm.

By adopting the technical scheme, the substitution degree and the particle size of cellulose have certain influence on the emulsion performance, so that the low-temperature anti-cracking elongation and the alkali treatment anti-cracking elongation of the emulsion coating can be partially improved, and the water contact angle is further increased; this is probably because the carboxymethyl cellulose with a degree of substitution of 0.7 has better rheological properties, stability; the carboxymethyl cellulose with the particle size of less than 100 mu m has good dispersibility, so that the carboxymethyl cellulose is not easy to generate the agglomeration phenomenon.

The application provides a preparation method of an emulsion applied to a PP material, which comprises the following steps:

s1, preparing a mixed solution:

adding polysilazane resin, an additive, dimethylacetamide and other raw materials except chlorinated polyolefin into a reaction vessel, and stirring to obtain a mixed solution;

s2, heating to 80-120 ℃, adding chlorinated polyolefin, and stirring for 20-30min;

s3, reducing the temperature to 30-45 ℃, stirring and emulsifying to obtain the emulsion applied to the PP material.

Preferably, the step S1 further includes the steps of:

s11: mixing carboxymethyl cellulose and lithium chloride, dissolving in dimethylacetamide, and adding casein glue in a stirring state to obtain a pre-solution;

s12: and (3) placing polysilazane resin into a reaction container, adding the pre-solution under stirring, and continuing stirring for 20-30min to obtain the mixed solution.

By adopting the technical scheme, the emulsion applied to the PP material is simple to prepare and convenient for mass production, and the dispersion performance of each component can be improved by firstly mixing the carboxymethyl cellulose and the lithium chloride and then dissolving the mixture into the dimethylacetamide, and adding the mixture into a reaction vessel to be mixed with polysilazane resin in a stirring state, so that the emulsion property is more stable.

A third object of the present application is to provide the use of an emulsion applied to PP material; the modified polypropylene resin is used for preparing coatings and paints, has good water-repellent capability, high adhesive force and high crack resistance, and can be firmly applied to the surface of PP materials.

In summary, the present application includes at least one of the following beneficial technical effects:

1. the emulsion prepared from polysilazane resin, chlorinated polyolefin with chlorine content lower than 50wt% and carboxymethyl cellulose has high coating adhesive force and good hydrophobicity when being coated on a PP material, and the test piece after low-temperature and alkali treatment can reach elongation above 370, and peeling do not occur in a low-temperature freeze-thawing cycle test;

2. the substitution degree and the particle size of cellulose have a certain influence on the emulsion performance, so that the low-temperature anti-cracking elongation and the alkali treatment anti-cracking elongation of the emulsion coating can be partially improved, and the water contact angle is further increased; this is probably because the carboxymethyl cellulose with a degree of substitution of 0.7 has better rheological properties, stability; the carboxymethyl cellulose with the average particle size of less than 100 mu m has good dispersibility, so that the carboxymethyl cellulose is not easy to generate the agglomeration phenomenon;

3. the preparation method is simple and convenient for mass production, and the dispersion performance of each component can be improved by mixing the carboxymethyl cellulose and the lithium chloride firstly and then dissolving the mixture into the dimethylacetamide, and adding the mixture into a reaction vessel to be mixed with polysilazane resin under the stirring state, so that the emulsion property is more stable.

Drawings

FIG. 1 is a schematic illustration of a production flow of an embodiment of the present application.

FIG. 2 is a schematic flow chart of the preparation of the mixed liquor in the embodiment of the application.

Detailed Description

The present application will be described in further detail with reference to examples. The following examples are only illustrative of the present application and should not be construed as limiting the scope of the application. The following examples are conducted under conventional conditions or conditions recommended by the manufacturer, and the methods used are conventional methods known in the art, and the consumables and reagents used are commercially available unless otherwise specified. Unless otherwise defined, the technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. In addition, any method or material similar or equivalent to those described may be used in the present application.

Examples

Examples 1 to 3

Examples 1-3 provide an emulsion applied to PP materials, respectively.

The above examples differ in the parts by weight of the emulsion applied to the PP material, as shown in table 1.

The polysilazane resin has a number average molecular weight of 750-1000; the chlorinated polyolefin has a chlorine content of 48% or less, a degree of substitution of carboxymethyl cellulose of 0.4 and an average particle diameter of 100. Mu.m.

TABLE 1 composition of the components of the emulsions applied to PP materials provided in examples 1-3

A method for preparing the emulsion applied to PP material in examples 1-3, comprising the steps of:

s1, preparing a mixed solution:

placing polysilazane resin into a reaction vessel, adding carboxymethyl cellulose and dimethylacetamide into the reaction vessel under the condition of uniform stirring at 800-1200r/min, and stirring to obtain the mixed solution;

s2, heating to 80-120 ℃, adding chlorinated polyolefin into the mixed solution under the protection of nitrogen and stirring, and stirring for 20-30min;

s3, the temperature is reduced to 30-45 ℃ and stirring is continued for 1.5-2h, and the emulsion applied to the PP material is obtained through emulsification.

Examples 4 to 7

Examples 4-7 provide an emulsion for application to PP materials.

Examples 4-7 differ from example 2 in that examples 4-7 differ in the composition of the additive components used in the preparation of the emulsions applied to the PP material, as shown in Table 2.

TABLE 2 additive composition in emulsions applied to PP materials provided in examples 4-7

A method of preparing the emulsion applied to PP material of examples 4-7 comprising the steps of:

s1, preparing a mixed solution:

placing polysilazane resin into a reaction vessel, adding carboxymethyl cellulose, dimethylacetamide and casein glue into the reaction vessel under the condition of uniform stirring at 800-1200r/min, and stirring to obtain a mixed solution;

Example 8

Example 8 provides an emulsion applied to PP material.

Example 8 differs from example 5 in that in the preparation of the emulsion applied to PP material in example 8, 0.7 parts by mass of lithium chloride is also added.

A method of preparing an emulsion applied to PP material in example 8 comprising the steps of:

s1, preparing a mixed solution:

placing polysilazane resin into a reaction vessel, adding carboxymethyl cellulose, dimethylacetamide, casein glue and lithium chloride into the reaction vessel under the condition of uniform stirring at 800-1200r/min, and stirring to obtain a mixed solution;

Examples 9 to 12

Examples 9-12 provide an emulsion for application to PP materials.

Examples 9-12 differ from example 8 in that in the preparation of the emulsions applied to PP materials in examples 9-10, the amounts of lithium chloride added to dimethylacetamide are different.

Specifically, the results are shown in Table 3.

TABLE 3 additive composition in emulsions applied to PP materials provided in examples 9-12

Example 13

Example 13 provides an emulsion applied to PP material.

Example 13 differs from example 8 in that the polysilazane resin in example 13 has a number average molecular weight of 800 to 900.

Example 14

Example 14 provides an emulsion for application to PP materials.

Example 14 differs from example 13 in that the chlorinated polyolefin of example 14 has a chlorine content of 15 to 22% by weight.

Example 15

Example 15 provides an emulsion applied to PP material.

Example 15 differs from example 14 in that the degree of substitution of carboxymethyl cellulose in example 13 is 0.7.

Example 16

Example 16 provides an emulsion for application to PP materials.

Example 16 differs from example 15 in that the carboxymethyl cellulose in example 15 has an average particle size of 50. Mu.m.

Example 17

Example 17 provides an emulsion for application to PP materials.

Example 17 differs from example 16 in the method of preparation.

A method of preparing an emulsion for application to PP material in example 17, comprising the steps of:

s1, preparing a mixed solution:

s11, mixing carboxymethyl cellulose and lithium chloride, dissolving in dimethylacetamide, and adding casein glue in a stirring state to obtain a pre-solution; s12: placing polysilazane resin into a reaction vessel, adding a pre-solution into the reaction vessel under the condition of uniform stirring at 800-1200r/min, and continuously stirring for 20-30min;

s3, the temperature is reduced to 30-45 ℃ and stirring is continued for 1.5-2 hours, and the emulsion applied to the PP material is prepared by emulsification

Comparative example

Comparative example 1

Comparative example 1 differs from example 2 in that the chlorinated polyolefin has a chlorine content of more than 50wt% when the emulsion applied to the PP material is prepared.

Comparative example 2

Comparative example 2 differs from example 2 in that the chlorinated polyolefin was replaced by chlorinated polypropylene when the emulsion applied to the PP material was prepared.

Comparative example 3

Comparative example 3 differs from example 2 in that the polysilazane resin was replaced by bisphenol a type epoxy resin when the emulsion applied to the PP material was prepared.

Comparative example 4

Comparative example 4 differs from example 2 in that the carboxymethyl cellulose was replaced by hydroxypropyl methyl cellulose when the emulsion applied to the PP material was prepared.

Performance test

1. The low-temperature crack resistance elongation is that the tensile speed is 200mm/min under the condition that the material is stored for 1h at the temperature of minus 20 plus or minus 5 ℃ and then is recovered to the room temperature according to the specification of 9.2.1 in GB/T16777-2008.

2. The alkali-resistant and crack-resistant elongation (tensile property after alkali treatment) was carried out in accordance with the specification of 9.2.3 in GB/T16777-2008, and the tensile speed was 200mm/min.

3. And (3) performing freeze thawing performance test, namely setting 4 PP test pieces coated with emulsion into 1 group, reserving 1 test piece as a control sample, placing other 3 test pieces at normal temperature for 24 hours, placing the test pieces in tap water at the temperature of (23+/-2) DEG C for 18 hours, then placing the test pieces in a low-temperature test box at the temperature of (-20+/-2) DEG C for 3 hours, taking out the test pieces from the low-temperature test box, immediately placing the test pieces in an incubator at the temperature of (50+/-2) DEG C for 3 hours, namely 1 cycle, and repeating the cycle test according to the cycle test. During the test, a test piece is observed at the end of each cycle, whether the coating has cracking, delamination, falling, swelling and discoloration phenomena is judged, recorded and cycled for 5 times; and judging that at least 2 of the 3 test pieces meet the technical requirements.

4. And (3) testing the hydrophobicity performance, namely coating emulsion on the PP material, curing to form a test sample, and using purified water to measure the water contact angle, namely placing the cleaned test sample on a horizontal table, accurately adding a water drop to be tested into the test sample by a certain volume, shooting an image of the lower water drop by a camera, measuring the contact angle of the water drop on a picture by using related software, judging the hydrophilicity and the hydrophobicity according to the measured water contact angle result, wherein the larger the contact angle is, the more hydrophobic the material surface is.

5. Adhesion performance test (peel-resistant cross-hatch test).

The anti-stripping test of the coating is according to the cross-cut test of colored paint and varnish films (GB/T9286-2021), and the main test instrument is a cross-cut tester. Coating emulsion on PP material, solidifying to form test sample, horizontally dragging the cross-cut device for the second time and mutually perpendicular to the former time, twice marking out a plurality of small square squares, tearing the square squares after being stuck on the surface by using adhesive tape, and observing the peeling and falling conditions of the small square squares of the coating by using a magnifying glass.

If no lattice is removed from the surface of the coating, the peeling grade of the coating is 0 grade; if the coating cut intersections allow a small amount of coating to fall off and separate, but the area of the cross-hatch is not more than 5% the coating peel rating is 1; if the coating falls off at the intersection of the coating cuts or along the edges of the cuts, and the influence area is 5% -15%, the coating stripping grade is grade 2; if a large area of shedding is found along the cutting edge of the coating, and the impact area is 15% -35%, the peeling grade of the coating is 3; if the coating is fallen off along the cutting edge and the influence area is 35% -65%, the peeling grade of the coating is 4 grade; a coating peel rating of 5 was identified if severe peeling was found during the test with an impact area greater than 4.

Test results

Table 4 the results of the tests on the properties of the emulsions of examples 1 to 18 and comparative examples 1 to 4 are as follows:

analysis of results

The present application will be described in detail below in conjunction with the experimental data provided in tables 1-4.

By combining the examples 1-3, the comparative examples 1-4 and the detection results, the emulsion prepared by using polysilazane resin, chlorinated polyolefin with chlorine content lower than 50wt% and carboxymethyl cellulose in the examples 1-3 can reach the coating stripping grade below grade 2 when being coated on PP materials, the adhesive force is high, the water contact angle is above 110 ℃, the test piece after low temperature and alkali treatment can reach the elongation above 370, the peeling stripping does not occur in the 5-time low temperature freeze thawing cycle test, the adhesive force and the hydrophobic performance are better, the hydrophilic performance of the polysilazane resin is improved, the low temperature and the alkaline elongation at break of the emulsion are good, and the hydrophobicity is good; therefore, at low temperature, the inside of the coating is not easy to crack, the stability is high, the surface of the coating is not easy to condense water drops, the low-temperature brittleness of the emulsion coated on the PP material and paint and coating prepared by the emulsion at low temperature is overcome to a certain extent, and the coating has excellent application prospect.

Compared with example 2, the chlorinated polyolefin with chlorine content higher than 50wt% is used in comparative example 1, and the water contact angle of the prepared emulsion is smaller than 90 degrees, so that water drops are not easy to slip off when adhered to the surface of the emulsion, water drops on the surface of the coating are easy to condense, and water drops are easy to condense when applied under low-temperature and humid conditions.

Compared with example 2, the chlorinated polyolefin of comparative example 2 is replaced by chlorinated polypropylene, the adhesion performance of the emulsion is reduced to 5 grades, the emulsion coating is severely peeled off, peeling and peeling appear after 2 times of freeze thawing resistance, and the adhesive force and the low-temperature freeze thawing resistance performance are poor.

Compared with example 2, when the polysilazane resin of comparative example 3 is changed into bisphenol A epoxy resin, the adhesion performance of the emulsion is reduced to 5 levels, peeling and peeling can occur after 5 times of freeze thawing resistance, which is probably because the polysilazane resin has low surface energy and better fatigue resistance as a resin matrix, and various properties of the polysilazane resin can be changed under the action of adding chlorinated polyolefin and carboxymethyl cellulose; and the ether bond and the hydroxyl in the bisphenol A epoxy resin are polar groups, the interaction with chlorinated polyolefin and carboxymethyl cellulose is not obvious, the epoxy resin has higher wettability and poor wet heat resistance and weather resistance, so that the coating prepared under the component has poor adhesion.

Compared with example 2, when the carboxymethyl cellulose type is replaced by hydroxypropyl methyl cellulose in comparative example 4, the low-temperature anti-cracking elongation and the alkali treatment anti-cracking elongation are respectively reduced to 309% and 311%, and the influence of the different cellulose types on the anti-cracking elongation of the prepared emulsion is obvious, which is probably caused by the different dispersities of the different celluloses in the solvent system.

Therefore, the emulsion coated on the PP material is guaranteed to have excellent adhesive force, good anti-cracking elongation and low-temperature freeze thawing resistance, and when the surface water contact angle is more than 110 ℃, polysilazane resin, chlorinated polyolefin with chlorine content lower than 50wt% and carboxymethyl cellulose are necessary.

In combination with example 2, examples 4 to 7 and the detection result show that the carboxymethyl cellulose is replaced by casein glue, the performance change of the prepared emulsion is not obvious, but compared with the method that the carboxymethyl cellulose or the casein glue is singly added, after the carboxymethyl cellulose or the casein glue is mixed and added, the water contact angle of the prepared emulsion is obviously increased, the anti-cracking elongation is obviously improved, and the anti-cracking elongation and the hydrophobic performance are obviously improved, so that the anti-cracking elongation and the hydrophobic performance have synergistic effect, and the toughness and the ductility of the emulsion coating can be enhanced when the carboxymethyl cellulose and the casein glue are mixed and added, so that the components are uniformly dispersed inside, the surface connection stability is high, and the effect is compact.

As can be seen from the combination of examples 5, 8 and the test results, after adding lithium chloride, the coating stripping grade is reduced, the emulsion adhesion is improved, the hydrophobicity is increased, and the low-temperature anti-cracking elongation and the alkali-treated anti-cracking elongation are both improved, which is probably because after adding lithium chloride, the compatibility between the chlorinated polyolefin and the polysilazane resin and the additive can be promoted, the dispersion of the emulsion is strengthened, and the dispersion system supports each other, so that the stability is higher.

In comparison with example 8, examples 9 to 12 were further tested for the effect on the emulsion properties when lithium chloride and dimethylacetamide were added in different parts by mass and different ratios, and the ratio of lithium chloride to dimethylacetamide was tested to be 1 (6.7 to 14.4) and the ratio of lithium chloride to dimethylacetamide was 9 parts by mass and the ratio of lithium chloride to dimethylacetamide was 1:10.

As can be seen from the detection results of the examples 8 and 12-14, the number average molecular weight of the polysilazane resin is 800-900, the anti-cracking elongation of the emulsion is improved, and the water contact angle is increased; the chlorine content of chlorinated polyolefin is preferably 15-22wt%, the stripping grade reaches 0 grade, the water contact angle is increased to 160 degrees, the super-hydrophobic grade is achieved, and the phenomena of water drop adhesion and condensation in a low-temperature and humid environment can be reduced.

According to the detection results of the examples 14-16, the substitution degree and the particle size of cellulose have a certain influence on the performance of the emulsion, the emulsion prepared from carboxymethyl cellulose with the substitution degree of 0.7 is provided, the coating stripping grade reaches 0 grade, the emulsion prepared from carboxymethyl cellulose with the average particle size of 50 mu m is selected, the low-temperature anti-cracking elongation and the alkali treatment anti-cracking elongation can be partially improved, and the water contact angle is further increased. This may be that carboxymethyl cellulose with a degree of substitution of 0.7 has better rheology, stability; the carboxymethyl cellulose with the average particle size of 50 mu m has good dispersibility, improves the phenomenon that carboxymethyl cellulose molecules which are firstly contacted with water quickly absorb water and swell to form granules with dry inside and wet outside, and is not easy to generate the agglomeration.

It is understood from the results of examples 16 to 17 that the addition sequence of lithium chloride significantly improves the hydrophobic property, and this is probably because the addition of lithium chloride to dimethylacetamide can enhance the dispersion promoting effect of lithium chloride on other components.

The tests prove that the emulsion prepared in the embodiments 1-17 has higher adhesive force, does not explode paint at low temperature, has high anti-cracking elongation, does not peel off after freezing and thawing cycle, has large water contact angle and excellent hydrophobic property, can protect the surface of the PP substrate with large surface brittleness under the low temperature condition, and is suitable for application of the PP material in a low temperature and humidity environment, and particularly suitable for treatment of the surface of a PP coaming in a refrigeration house.

The present embodiment is only for explanation of the present application and is not to be construed as limiting the present application, and modifications to the present embodiment, which may not creatively contribute to the present application as required by those skilled in the art after reading the present specification, are all protected by patent laws within the scope of claims of the present application.

Claims

1. The emulsion applied to the PP material is characterized by being prepared from the following raw materials in parts by weight:

14-20 parts of polysilazane resin,

3-7 parts of chlorinated polyolefin,

0.3 to 0.7 part of additive,

6-9 parts of a solvent;

2. An emulsion for PP material according to claim 1, wherein the additive consists of carboxymethyl cellulose and casein glue in a mass ratio of (0.25-0.4): 1.

3. The emulsion of claim 1, wherein the starting material for preparing the emulsion further comprises 0.5 to 1.5 parts of lithium chloride.

4. An emulsion for PP material according to claim 3, wherein the mass ratio of said lithium chloride to said solvent is 1 (6.7-14.4).

5. An emulsion for PP materials according to claim 1 wherein the polysilazane resin has a number average molecular weight of 750 to 1000.

6. An emulsion for PP material according to claim 1, wherein the chlorinated polyolefin has a chlorine content of 15-22 wt.%.

7. An emulsion for PP material according to claim 1, wherein the degree of substitution of the carboxymethyl cellulose is 0.4-1.5.

8. An emulsion for PP material according to claim 1, wherein the average particle size of the carboxymethyl cellulose is less than 100. Mu.m.

9. A process for the preparation of an emulsion for application to PP material according to any of claims 1-8, characterized in that it comprises the following steps:

s1, preparing a mixed solution:

10. The method for preparing an emulsion for application to PP materials according to claim 9, wherein said step S1 further comprises the steps of:

s11: mixing carboxymethyl cellulose and lithium chloride, dissolving in a solvent, and adding casein glue in a stirring state to obtain a pre-solution;