CN112979880A

CN112979880A - Narrow-dispersion graft copolymerization ABS composition and preparation method thereof

Info

Publication number: CN112979880A
Application number: CN202110396395.1A
Authority: CN
Inventors: 刘伯军; 徐璐; 张明耀; 胡艺伟; 张艳海; 刘洋; 吴高澄
Original assignee: Changchun University of Technology
Current assignee: Changchun University of Technology
Priority date: 2021-04-13
Filing date: 2021-04-13
Publication date: 2021-06-18
Anticipated expiration: 2041-04-13
Also published as: CN112979880B

Abstract

The invention discloses a narrow dispersion graft copolymerization ABS composition and a preparation method thereof, wherein a pre-emulsion fast feeding mode is adopted to reduce the graft polymerization time and reduce the energy consumption; dropwise adding alkali liquor to maintain the pH value of the latex unchanged, reducing the possibility of rubber particle aggregation and obtaining narrow-distribution grafted rubber particles; the addition of the ethylene unsaturated carboxylic acid ester monomer serving as a good solvent of the diene rubber effectively improves the final monomer conversion rate in the grafting process, reduces the residual quantity of the vinyl benzene monomer and the vinyl cyanide monomer caused by rapid feeding, reduces the influence of side reactions such as cyclization of the vinyl cyanide monomer and the like on the apparent performance of the ABS thermoplastic resin composition, simultaneously diffuses the ethylene unsaturated carboxylic acid ester monomer into rubber particles, increases internal grafting and enables the interior of the rubber particles to be properly crosslinked, improves the dispersibility and toughening effect of the ABS graft copolymer in matrix resin, and finally obtains the thermoplastic resin composition with good apparent performance and excellent impact resistance.

Description

Narrow-dispersion graft copolymerization ABS composition and preparation method thereof

Technical Field

The invention belongs to the technical field of high polymer materials, and particularly relates to an ABS composition and an efficient preparation method of a narrow dispersion graft copolymer thereof.

Background

ABS resin is one of the representative works of human beings in the field of materials, and is widely used in the fields of housings of home appliances and the like due to its excellent mechanical and aesthetic properties. Along with the improvement of living standard, the requirement of people on the aesthetic degree of living goods is also improved, and the market demands on the whiteness of the shells of household air conditioners and refrigerators are more obvious.

At present, the industrial preparation method of ABS resin mainly comprises a continuous bulk method and an emulsion graft blending method, and although continuous bulk polymerization technology is continuously developed in recent years, the continuous bulk polymerization technology cannot be fully accepted by the market due to the immature process. At present, the mainstream ABS preparation technology is still an emulsion grafting-bulk SAN blending method, and the process inevitably has monomer residues in the emulsion grafting process, which is one of the important reasons for reducing the whiteness of the ABS resin, so that the conversion rate in the grafting process is improved, the grafting time is shortened, the product quality can be directly improved, the production cost is reduced, the device efficiency is improved, the production energy consumption is reduced, the environment is better protected, and the process has very important social significance. Meanwhile, how to keep the stable shape of the rubber particles while improving the grafting efficiency is also important for ensuring that the ABS composition has good impact resistance.

In the prior art, the patent CN109071916A for reducing the content of useless residues in the graft emulsion reduces the content of the unnecessary residues by adding the phosphate ester reactive emulsifier which can be used as a metal deactivator, and improves the impact resistance of the ABS composition by improving the compatibility between the ABS graft copolymer and the aromatic vinyl compound-vinyl cyanide compound copolymer through the phosphate ester reactive emulsifier. The patent CN104693636 for improving the conversion rate of the graft polymer improves the conversion rate by adding a bifunctional reactive monomer at the later stage of grafting, the patent improves the reaction conversion rate by introducing an ethylene unsaturated carboxylic ester monomer, utilizes double bonds in unsaturated carboxyl and simultaneously limits ethylene to obtain another double bond, and enables the interior of rubber particles to be properly crosslinked, the proper crosslinking is beneficial to keeping the optimal toughening form of the rubber particles and improving the dispersibility, and the limitation of ester is to reduce the devolatilization boiling point of the introduced monomer and reduce the energy consumption of devolatilization, liquid removal and gas removal. The prior patent CN105189588A mentions a preparation method of a small-particle-size bimodal grafting structure to improve the surface gloss of the ABS resin composition, but various schemes in the prior art have the defects of complex flow, long grafting time, low conversion rate and the like, and the industrial production is difficult to ensure.

Therefore, the problem to be solved by those skilled in the art is how to provide an emulsion grafting method with simple operation flow, short grafting time, high grafting conversion rate and narrow dispersion of rubber particles.

Disclosure of Invention

In view of the above, the invention provides an ABS graft copolymer with short grafting time, high grafting conversion rate and narrow internal crosslinking dispersion, and an ABS composition with excellent whiteness and better impact performance is obtained by melt blending the graft copolymer and a matrix resin.

In order to achieve the purpose, the invention adopts the following technical scheme:

a narrow-dispersion graft copolymerization ABS composition comprises the following components in parts by weight: 40-60 parts of diene latex dry base, 28.5-43 parts of vinyl benzene monomer, 11.5-17 parts of vinyl cyanide monomer, 3.5-5.15 parts of ethylene unsaturated carboxylic ester monomer, 0.15-0.225 part of alkali liquor dry base, 0.4-0.6 part of emulsifier, 0.2-0.3 part of initiator, 0.5-0.75 part of redox system and 0.8-1.2 parts of antioxidant.

Preferably, the diene latex is one of polybutadiene latex and butadiene-styrene latex.

Preferably, the vinyl benzene monomer is one of styrene, methyl styrene, p-methyl styrene and vinyl toluene, and is preferably styrene.

Preferably, the vinyl cyanide monomer is acrylonitrile, methacrylonitrile or a mixture thereof, preferably acrylonitrile.

Preferably, the ethylene unsaturated carboxylic ester monomer is one of methyl acrylate, ethyl acrylate, butyl acrylate and methyl methacrylate, and is preferably methyl methacrylate.

Preferably, the alkali liquor is one of sodium hydroxide and potassium hydroxide, and potassium hydroxide is preferred; the emulsifier is one or more of free alkyl aryl sulfonate, rosin acid alkyl salt and fatty acid salt, preferably disproportionated potassium rosinate soap and sodium dodecyl sulfate; the initiator is one or more of potassium persulfate, benzoyl peroxide, cumene hydroperoxide, di-tert-butyl peroxide and azobisisobutyronitrile, and the preferred initiator is the cumene hydroperoxide.

Preferably, the redox system is one of a composition of fructose, ferrous sulfate and sodium pyrophosphate or a composition of ethylenediaminetetraacetic acid disodium salt, sodium formaldehyde sulfoxylate and ferrous sulfate, wherein the mass ratio of the fructose, the ferrous sulfate and the sodium pyrophosphate is 10:4:1, the mass ratio of the sodium formaldehyde sulfoxylate, the ferrous sulfate and the ethylenediaminetetraacetic acid disodium salt is 10:4:1, and the antioxidant is an antioxidant AO-8020 and is produced by Bo Yu Xiang Shi Limited company in Guilin.

A preparation method of a narrow-dispersion graft copolymerization ABS composition comprises the following steps:

the method comprises the following steps: preparation of ABS graft polymers

(1.1) preparing a pre-emulsion from an emulsifier, a vinyl benzene monomer, a vinyl cyanide monomer, 4/5 (the total amount of an initiator) and water for later use;

(1.2) preparing an oxidation-reduction system into an aqueous solution according to a proportion, adding the aqueous solution into diene latex, controlling the reaction temperature to be 55-60 ℃, and injecting the pre-emulsion into the diene latex in a dropping feeding manner at the rotating speed of 300rpm for 50-70min, and simultaneously injecting alkali liquor with the mass concentration of 5% -10% in the dropping feeding manner to keep the pH value of the reaction system between 9.4 and 9.7;

(1.3) after the feeding is finished, heating to 70-75 ℃, continuously injecting ethylene unsaturated carboxylic ester monomers into the reaction system in the step (1.2) in a dropwise feeding mode, wherein the feeding time is 15-20min, supplementing the rest initiator after the feeding is finished, keeping the temperature for curing for 50min, cooling to less than or equal to 60 ℃, adding an antioxidant emulsion, uniformly mixing, adding a 0.3-0.4% sulfuric acid aqueous solution, heating to 85-95 ℃ for flocculation, filtering, washing and drying to obtain an ABS graft polymer;

step two: preparation of narrow dispersion graft copolymerization ABS composition

And (3) blending the ABS graft polymer prepared in the step one with SAN matrix resin at 220 ℃ by using an extruder to obtain the narrow-dispersion graft copolymerization ABS composition.

Preferably, the weight ratio of the vinyl benzene monomer to the vinyl cyanide monomer in the pre-emulsion of step (1.1) is 2.5: 1, the proportion is the optimal compatibility proportion of the aromatic vinyl compound-vinyl cyan compound copolymer in the ABS graft copolymer.

Preferably, the weight ratio of the ethylene unsaturated carboxylic ester monomer to the vinyl cyanide monomer in the step (1.3) is 0.3: 1, the monomer conversion rate can reach the maximum value, and the formation of useless polymers by the ethylene unsaturated carboxylic ester monomers is avoided.

According to the technical scheme, compared with the prior art, the invention discloses and provides the narrow-dispersion graft copolymerization ABS composition and the preparation method thereof, the vinyl benzene monomer and the vinyl nitrile monomer adopt a pre-emulsion feeding mode, compared with the mode that an oil phase is introduced into monomer feeding, the pre-emulsion can more rapidly carry out graft polymerization with diene latex, the grafting time is shortened, and the polymerization rate is improved; alkali liquor is injected into butadiene latex in a dropwise feeding mode to maintain the pH of the latex unchanged, so that the pH value of the latex can be prevented from being reduced by side reactions such as aldehyde group oxidation and sulfurous acid decomposition in the reaction, the complex reaction of ferrous ions and a chelating agent is ensured, the reduction of the grafting reaction rate is avoided, the pH is stabilized at 9.4-9.7, and the influence on the grafting polymerization rate caused by the hydroxyl coordination effect of metal ions due to overhigh pH is prevented; in the late stage of grafting, ethylene unsaturated carboxylic ester monomer is injected into diene latex in the same way, double bonds in unsaturated carboxyl are utilized and are limited to ethylene to obtain another double bond, the reaction conversion rate is improved, the interior of rubber particles is properly crosslinked, the proper crosslinking is beneficial to keeping the optimal toughening form of the rubber particles and improving the dispersity, and the limitation of ester is to reduce the devolatilization boiling point of the introduced monomer and reduce the energy consumption of devolatilization, liquid removal and gas removal. The final ABS graft copolymer has narrow distribution of rubber particles, particle size difference smaller than 100nm, final conversion rate of latex after graft polymerization over 98%, apparent whiteness over 55, and impact strength over 200J/m.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the provided drawings without creative efforts.

FIG. 1 is a transmission electron microscope photograph of an ABS graft copolymer prepared in example 1 of the present invention;

FIG. 2 is a transmission electron microscope photograph of an ABS graft copolymer prepared in comparative example 2 of the present invention;

FIG. 3 is a transmission electron microscope photograph of an ABS graft copolymer prepared in comparative example 3 of the present invention;

FIG. 4 is a transmission electron microscope photograph of an ABS graft copolymer prepared in comparative example 4 of the present invention.

Detailed Description

The technical solutions of the present invention will be described clearly and completely with reference to the following embodiments of the present invention, and it should be understood that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Example 1

The method comprises the following steps: preparation of ABS graft polymers

(1.1) oscillating 0.4 part of emulsifier sodium dodecyl sulfate, 22.5 parts of deionized water, 40 parts of styrene and acrylonitrile monomers in total, wherein the ratio of styrene to acrylonitrile is 2.5/1, and 0.12 part of cumene hydroperoxide to form pre-emulsion;

(1.2) weighing 0.04 part of sodium pyrophosphate, 0.1 part of fructose, 0.01 part of ferrous sulfate, 5 parts of deionized water and 0.04 part of cumene hydroperoxide, dissolving and mixing, placing in 60 parts of dry polybutadiene latex, controlling the reaction temperature to be 57 ℃, injecting the pre-emulsion into the polybutadiene latex in a dropping feeding mode under the condition of a rotating speed of 300rpm, controlling the reaction temperature to be 57 ℃, and injecting a potassium hydroxide solution with a mass concentration of 5% in a dropping feeding mode for 60min, wherein the potassium hydroxide is 0.15 part, the deionized water is 2.85 parts, and the pH of the reaction system is kept between 9.4 and 9.7;

(1.3) after the feeding is finished, heating to 74 ℃, continuously injecting 3.43 parts of ethylene unsaturated carboxylic ester monomer methyl methacrylate into the reaction system in the step (1.2) in a dropwise feeding manner, feeding for 15min, supplementing 0.04 part of cumene hydroperoxide after the feeding is finished, keeping the temperature for curing for 50min, cooling to be less than or equal to 60 ℃, then adding 0.8 part of antioxidant AO-8020, uniformly mixing, adding 0.4 wt% sulfuric acid aqueous solution, heating to 93 ℃, flocculating for 5min, filtering, washing and drying to obtain ABS grafted polymer powder;

Mixing the ABS graft polymer powder prepared in the step one and styrene acrylonitrile copolymer according to the weight ratio of 25: 75, and finally obtaining the ABS composition.

The ABS graft copolymer conversions are listed in Table 1 along with the whiteness values and impact strength values of the ABS compositions.

Example 2

The method comprises the following steps: preparation of ABS graft polymers

(1.1) oscillating 0.6 part by weight of emulsifier disproportionated potassium rosinate soap, 33.75 parts by weight of deionized water, 60 parts by weight of styrene and acrylonitrile monomers, wherein the ratio of styrene to acrylonitrile is 2.5/1, and 0.18 part by weight of cumene hydroperoxide is used as pre-emulsion;

(1.2) weighing 0.06 part of sodium pyrophosphate, 0.15 part of fructose, 0.015 part of ferrous sulfate, 7.5 parts of deionized water and 0.06 part of cumene hydroperoxide, dissolving and mixing, placing in 40 parts of dry polybutadiene latex, controlling the reaction temperature to be 57 ℃, injecting the pre-emulsion into the polybutadiene latex in a dropping feeding mode under the condition of the rotation speed of 300rpm, feeding for 60min, and injecting a potassium hydroxide solution with the mass concentration of 5% in the dropping feeding mode, wherein 0.225 part of potassium hydroxide and 4.275 parts of deionized water keep the pH of the reaction system between 9.4 and 9.7;

(1.3) after the feeding is finished, heating to 74 ℃, continuously injecting 5.15 parts of ethylene unsaturated carboxylic ester monomer methyl methacrylate into the reaction system in the step (1.2) in a dropwise feeding mode, feeding for 15min, supplementing 0.04 part of cumene hydroperoxide after the feeding is finished, keeping the temperature for curing for 50min, cooling to be less than or equal to 60 ℃, then adding 0.8 part of antioxidant, uniformly mixing, adding 0.4 wt% sulfuric acid aqueous solution, heating to 93 ℃ for flocculation for 5min, and then filtering, washing and drying to obtain ABS graft polymer powder;

Mixing the ABS graft polymer powder prepared in the step one and styrene acrylonitrile copolymer according to the weight ratio of 37.5: and blending and extruding the mixture according to the proportion of 62.5 for granulation to finally obtain the ABS composition.

Comparative example 1

The preparation process of the ABS graft copolymer was the same as that described in example 1, except that after the addition of the pre-emulsion was completed, the temperature was raised to 74 ℃ without adding the ethylenically unsaturated carboxylic acid ester monomer methyl methacrylate, the contents of the other components were completely the same as those in example 1, and the conversion of the ABS graft copolymer, the whiteness value and the impact strength value of the ABS composition were as shown in Table 1.

Comparative example 2

The ABS graft copolymer was prepared by the same procedure as described in example 1, except that the 5% potassium hydroxide solution was not continuously injected simultaneously with the pre-emulsion feed. But an equal part of potassium hydroxide solution is added into the ABS graft latex at the end of the reaction, and the contents of other components are completely the same as those in example 1. The ABS graft copolymer conversions are listed in Table 1 along with the whiteness values and impact strength values of the ABS compositions.

Comparative example 3

The ABS graft copolymer was prepared as described in example 1, except that 10% potassium hydroxide solution was continuously injected simultaneously with the pre-emulsion feed, 0.45 parts potassium hydroxide, 4.275 parts deionized water, and the emulsion pH was maintained at about 12. The contents of other components are exactly the same as in example 1. The ABS graft copolymer conversions are listed in Table 1 along with the whiteness values and impact strength values of the ABS compositions.

Comparative example 4

The preparation of the ABS graft copolymer was carried out as described in example 1, except that the pre-emulsion feed time was extended to 180 min. The contents of other components are exactly the same as in example 1. The ABS graft copolymer conversions are listed in Table 1 along with the whiteness values and impact strength values of the ABS compositions.

Comparative example 5

The ABS graft copolymer was prepared by the same procedure as described in example 1, except that the reaction temperature was maintained at 65 ℃ during the pre-emulsion feed. The contents of other components are exactly the same as in example 1. The ABS graft copolymer conversions are listed in Table 1 along with the whiteness values and impact strength values of the ABS compositions.

TABLE 1 conversion of ABS graft copolymers with whiteness values and impact strength values of ABS compositions

As can be seen from Table 1 and FIGS. 1-4, the graft copolymer and the composition according to the present invention have more excellent properties.

The embodiments in the present description are described in a progressive manner, each embodiment focuses on differences from other embodiments, and the same and similar parts among the embodiments are referred to each other. The device disclosed by the embodiment corresponds to the method disclosed by the embodiment, so that the description is simple, and the relevant points can be referred to the method part for description.

The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A narrow-dispersion graft copolymerization ABS composition is characterized by comprising the following components in parts by weight: 40-60 parts of diene latex dry base, 28.5-43 parts of vinyl benzene monomer, 11.5-17 parts of vinyl cyanide monomer, 3.5-5.15 parts of ethylene unsaturated carboxylic ester monomer, 0.15-0.225 part of alkali liquor dry base, 0.4-0.6 part of emulsifier, 0.2-0.3 part of initiator, 0.5-0.75 part of redox system and 0.8-1.2 parts of antioxidant.

2. The narrow dispersion graft copolymer ABS composition of claim 1, wherein the diene latex is one of polybutadiene latex and butadiene-styrene latex.

3. The narrow dispersion graft copolymer ABS composition of claim 1, wherein the vinyl benzene monomer is one of styrene, methyl styrene, p-methyl styrene, and vinyl toluene.

4. The narrow dispersion graft copolymer ABS composition of claim 1, wherein the vinyl cyanide monomer is acrylonitrile, methacrylonitrile, or a mixture thereof.

5. The narrow dispersion graft copolymer ABS composition of claim 1, wherein the ethylenically unsaturated carboxylic acid ester monomer is one of methyl acrylate, ethyl acrylate, butyl acrylate, and methyl methacrylate.

6. The narrow dispersion graft copolymer ABS composition of claim 1, wherein the alkali solution is one of sodium hydroxide and potassium hydroxide, the emulsifier is one or more of free alkyl aryl sulfonate, rosin acid alkyl salt, and fatty acid salt, and the initiator is one or more of potassium persulfate, benzoyl peroxide, cumene hydroperoxide, di-t-butyl peroxide, and azobisisobutyronitrile.

7. The narrow-dispersion graft copolymer ABS composition according to claim 1, wherein the redox system is one of a composition of fructose, ferrous sulfate and sodium pyrophosphate or a composition of ethylenediaminetetraacetic acid disodium salt, sodium formaldehyde sulfoxylate and ferrous sulfate, wherein the mass ratio of fructose, ferrous sulfate and sodium pyrophosphate is 10:4:1, the mass ratio of sodium formaldehyde sulfoxylate, ferrous sulfate and ethylenediaminetetraacetic acid disodium salt is 10:4:1, and the antioxidant is antioxidant AO-8020.

8. A preparation method of a narrow-dispersion graft copolymerization ABS composition is characterized by comprising the following steps:

the method comprises the following steps: preparation of ABS graft polymers

(1.3) after the feeding is finished, heating to 70-75 ℃, continuously injecting ethylene unsaturated carboxylic ester monomers into the reaction system in the step (1.2) in a dropwise feeding mode, wherein the feeding time is 15-20min, supplementing the rest initiator after the feeding is finished, keeping the temperature for curing for 50min, cooling to less than or equal to 60 ℃, adding an antioxidant emulsion, uniformly mixing, adding a 0.3-0.4 wt% sulfuric acid aqueous solution, heating to 85-95 ℃ for flocculation, filtering, washing and drying to obtain an ABS graft polymer;

And (3) blending the ABS graft polymer prepared in the step one with matrix resin at high temperature to obtain the narrow-dispersion graft copolymerization ABS composition.

9. The method for preparing a narrow-dispersion ABS graft copolymer according to claim 8, wherein the weight ratio of the vinyl benzene monomer to the vinyl cyanide monomer in the pre-emulsion of step (1.1) is 2.5: 1.

10. the method for preparing a narrow-dispersion ABS graft copolymer as claimed in claim 8, wherein the weight ratio of the amount of the ethylenically unsaturated carboxylic acid ester monomer to the vinyl cyanide monomer in step (1.3) is 0.3: 1.