CN116355150A

CN116355150A - Preparation method of polybutadiene latex and prepared ABS resin

Info

Publication number: CN116355150A
Application number: CN202310298049.9A
Authority: CN
Inventors: 赵以兵; 冯兴磊; 孙一峰
Original assignee: Wanhua Chemical Group Co Ltd
Current assignee: Wanhua Chemical Group Co Ltd
Priority date: 2023-03-24
Filing date: 2023-03-24
Publication date: 2023-06-30

Abstract

The invention provides a preparation method of polybutadiene latex, which comprises the steps of modifying nano silicon dioxide by adopting a polymerizable silane coupling agent, firstly polymerizing and coating a layer of high-crosslinking polybutadiene rubber on the surface of the nano silicon dioxide, then polymerizing and coating a layer of low-crosslinking polybutadiene rubber to prepare the polybutadiene latex with a three-layer composite core-shell structure of nano silicon dioxide-high-crosslinking polybutadiene-low-crosslinking polybutadiene, and finally adding emulsified silicone oil, wherein the emulsified silicone oil is compatible with the polymerized polybutadiene latex in nano scale, and finally the special modified polybutadiene latex is obtained. The ABS resin prepared from the latex has higher impact strength and high rigidity, and also has excellent and durable abnormal sound resistance.

Description

Preparation method of polybutadiene latex and prepared ABS resin

Technical Field

The invention belongs to the field of polymers, and particularly relates to a preparation method of polybutadiene latex and ABS resin prepared by the preparation method.

Background

With the continuous improvement of consumer demands on life quality, ABS materials are increasingly required to have both excellent intrinsic performance quality and good appearance quality in fields of home appliances, automobiles, communication equipment, computers and the like in which ABS resins are widely used, for example, industries gradually have higher demands on mechanical properties of ABS resins for automotive interior parts and the like (i.e., properties such as anti-friction abnormal sound and the like must be considered in terms of impact strength and rigidity).

The ABS resin is structurally obtained by toughening and modifying the matrix SAN resin by adopting elastic nano-scale spherical rubber particles, the modified SAN resin is changed from a brittle material to a tough material, namely, the impact resistance of the SAN resin is improved by adding rubber particles, but the rigidity of the matrix SAN resin such as tensile strength, bending strength and the like is obviously reduced due to the addition of a rubber phase. At present, the rigidity loss is mainly compensated by increasing the proportion of AN monomers in a formula and the molecular weight of SAN resin in the preparation of SAN resin in the industry, but the two methods can bring about obvious increase of the viscosity of a system in the polymerization process, so that on one hand, the devolatilization difficulty of a product is increased, the residue of volatile substances in the product is increased, on the other hand, the conveying difficulty of the product is also increased, and the production efficiency is reduced.

In addition, when the ABS resin is extruded or collided in the using process, when the moment of external force is smaller than the friction force, the materials contacted with each other do not have the phenomenon of sliding, so that abnormal sound is not generated; once the external force moment is larger than a certain value of friction force, the material can suddenly slide, and then the material can generate instantaneous and intense vibration to generate crunchy noise. Patent CN107177156a discloses a preparation method of high damping noise reduction ABS, which improves damping of a material through an elastomer TPU, so that a good noise reduction effect is obtained, but the rigidity of the material is obviously reduced through adding rubber or an elastomer, so that application of the material is limited to a certain extent. CN112759878A discloses a silent HIPS alloy composition, a preparation method and application thereof, which adds a low surface energy component in a form of physical blending in a resin alloy system, so that the noise performance is obviously improved compared with that of common HIPS and alloy resins, but the anti-abnormal sound auxiliary agent in the form of physical dispersion exists in the resin, and the low surface energy auxiliary agent is easy to migrate along with the prolonged service period due to poor compatibility, so that the long-acting anti-abnormal sound effect cannot be provided, and meanwhile, the system has a loss of impact strength such as the resin due to excessive addition of the auxiliary agent.

Therefore, the research and preparation of the ABS resin with high impact strength, high rigidity and excellent lasting abnormal sound resistance have important practical significance.

Disclosure of Invention

The invention aims to provide a preparation method of polybutadiene latex, which comprises the steps of modifying nano silicon dioxide by adopting a polymerizable silane coupling agent, firstly polymerizing and coating a layer of high-crosslinking polybutadiene rubber on the surface of the nano silicon dioxide, then polymerizing and coating a layer of low-crosslinking polybutadiene rubber, preparing the polybutadiene latex with a three-layer composite core-shell structure of nano silicon dioxide-high-crosslinking polybutadiene-low-crosslinking polybutadiene, finally adding emulsified silicone oil, and finally obtaining the special modified polybutadiene latex after the nano silicon dioxide-high-crosslinking polybutadiene-low-crosslinking polybutadiene is compatible with the polymerized polybutadiene latex in nano scale.

The modified polybutadiene latex particles have the advantages that the inner core of the modified polybutadiene latex particles is hard nano silicon dioxide, the middle layer is a polybutadiene layer with higher crosslinking degree, and the rigidity performance of the ABS resin after blending can be effectively improved by the synergistic effect of the modified polybutadiene latex particles and the middle layer; in addition, by adding a proper amount of chain transfer agent in a specified conversion rate interval, the gel content of the outer layer polybutadiene is controlled to be in a lower level, and the molecular chain of the low gel polybutadiene is rich in more residual double bonds, so that the grafting of a styrene and acrylonitrile mixed monomer is facilitated, the grafting rate is improved, the compatibility of the ABS rubber powder with high grafting rate and SAN resin is better, the toughening efficiency is improved, and the impact resistance of the resin is also improved; finally, because the silane coupling agent added into the emulsified silicone oil and the latex at the later stage of the reaction has structural similarity, the emulsified silicone oil can be mixed and compatible with the polybutadiene latex at the nanometer scale, so that the silicon compound with low surface energy can be uniformly and stably dispersed in the ABS resin phase along with the polybutadiene latex, and the resin is endowed with excellent and durable abnormal sound prevention performance.

The invention aims at realizing the following technical scheme:

in a first aspect, the present invention provides a method for preparing polybutadiene latex, comprising the steps of, in parts by weight:

adding 40-60 parts of first deionized water, 1-5 parts of first emulsifier, 20-40 parts of water-soluble organic solvent, 1-5 parts of sodium hydroxide, 1-5 parts of silicon dioxide and 1-10 parts of silane coupling agent into a reactor, starting stirring, heating the reactor to 55-85 ℃ and preserving heat for 20-120min;

adding 60-100 parts of second deionized water, 110-150 parts of butadiene, 1-5 parts of second emulsifier, 1-5 parts of polymerizable cross-linking agent, 1-5 parts of electrolyte and 1-5 parts of initiator into a reactor to continue polymerization reaction;

when the butadiene conversion rate is more than or equal to 50% and less than or equal to 65%, adding 1-5 parts of chain transfer agent into the reaction kettle, and continuing the polymerization reaction;

when the butadiene conversion rate is more than or equal to 90% and less than or equal to 98%, adding 1-5 parts of emulsified silicone oil, uniformly stirring, cooling the reactor to normal temperature, and filtering to obtain the polybutadiene latex with a three-layer core-shell structure.

Preferably, the method comprises the following steps of, in parts by weight:

adding 45-55 parts of first deionized water, 2-4 parts of first emulsifying agent, 25-35 parts of water-soluble organic solvent, 2-4 parts of sodium hydroxide, 2-4 parts of silicon dioxide and 3-7 parts of silane coupling agent into a reactor, starting stirring, heating the reactor to 60-80 ℃ and preserving heat for 30-90min;

adding 70-90 parts of second deionized water, 120-140 parts of butadiene, 2-4 parts of second emulsifier, 2-4 parts of polymerizable cross-linking agent, 2-4 parts of electrolyte and 2-4 parts of initiator into a reactor to continue polymerization reaction;

when the butadiene conversion rate is more than or equal to 55% and less than or equal to 60%, adding 2-4 parts of chain transfer agent into the reaction kettle, and continuing the polymerization reaction;

adding emulsified silicone oil when the butadiene conversion rate is more than or equal to 92% and less than or equal to 96%, stirring uniformly, cooling the reactor to normal temperature, and filtering to obtain the polybutadiene latex with a three-layer core-shell structure.

In the method of the present invention, the water-soluble organic solvent has a solubility of not less than 20 parts by weight in 100 parts by weight of water at 25 ℃, for example, one or more selected from methanol, ethanol, N-propanol, isopropanol, N-butanol, isoamyl alcohol, ethylene glycol, N-dimethylformamide, tetrahydrofuran, preferably ethanol and/or isopropanol.

In the method of the present invention, the silica is a nano-sized silica particle, preferably a silica particle having a size of 10 to 50 nm.

In the method of the present invention, the silane coupling agent is selected from one or more of alkoxysilane containing at least one vinyl group, preferably vinyltrimethoxysilane, vinyltriethoxysilane, vinyltris (β -methoxyethoxy) silane, vinyltriisopropoxysilane, γ -methacryloxypropyl trimethoxysilane.

In the method of the invention, the first emulsifier is consistent or inconsistent with the second emulsifier, and is selected from one or more of potassium oleate, disproportionated potassium abietate, sodium dodecyl sulfate, sodium dodecyl benzene sulfonate and dioctyl sodium sulfonate.

In the method of the present invention, the polymerizable crosslinking agent is a polymerizable monomer having a multiolefin double bond, preferably one or more of allyl methacrylate, allyl acrylate, divinylbenzene, 1, 4-butanediol dimethacrylate, ethylene glycol dimethacrylate.

In the method of the invention, the electrolyte is one or more of potassium bicarbonate, potassium carbonate, sodium bicarbonate, sodium carbonate and sodium tripolyphosphate.

In the method of the present invention, the initiator is selected from one or more of inorganic peroxides and organic peroxides, preferably one or more of potassium persulfate, sodium persulfate, and ammonium persulfate.

In the process of the present invention, the chain transfer agent is t-dodecyl mercaptan.

In the method of the invention, the emulsified silicone oil is organic silicon mainly composed of methyl polysiloxane, preferably AFE of Dow Corning company ^TM 0120、AFE ^TM 1410、AFE ^TM 3168 and/or BYK from BYK company ^TM 024、BYK ^TM 028, one or more of the following.

In a second aspect, the present invention provides an ABS resin prepared from the polybutadiene latex prepared by the method of the present invention:

in the present invention, the prepared polybutadiene latex is grafted, coagulated, dehydrated and dried to obtain ABS rubber powder, and then blended with SAN resin to obtain ABS resin by granulating, which is a conventional technology in the art. The specific operation of grafting, condensing, filtering, dehydrating and drying polybutadiene latex to obtain ABS rubber powder can be referred to pages 36-58 in book ABS resin production practice and application written by Soxhlet and the like, and the specific operation of blending, extruding and granulating the ABS rubber powder and SAN resin to obtain ABS resin can be referred to pages 68-74 in the book.

The invention has the beneficial effects that:

the invention provides a preparation method of polybutadiene latex, which comprises the steps of modifying nano silicon dioxide by adopting a polymerizable silane coupling agent, firstly polymerizing and coating a layer of high-crosslinking polybutadiene rubber on the surface of the nano silicon dioxide, then coating a layer of low-crosslinking polybutadiene rubber, preparing the polybutadiene latex with a three-layer composite core-shell structure of nano silicon dioxide-high-crosslinking polybutadiene-low-crosslinking polybutadiene, and finally adding emulsified silicone oil, wherein the emulsified silicone oil is compatible with the polymerized polybutadiene latex in nano scale, and finally obtaining the special modified polybutadiene latex.

The ABS resin prepared from the latex has higher impact strength and high rigidity, and also has excellent and durable abnormal sound resistance.

Detailed Description

For a better understanding of the technical solution of the present invention, the following examples are further described below, but the present invention is not limited to the following examples.

The raw material source information in the following examples and comparative examples of the present invention are commercially available, unless otherwise specified.

In the following examples and comparative examples of the present invention, the test methods and standards for the properties of the intermediate product and resin are as follows:

butadiene conversion test method: a sample of 0.05g was taken into a 20ml headspace bottle, diluted to 1.00g with DMF, and analyzed by gas chromatograph to test for residual butadiene monomer content. Will test the knot

The butadiene conversion is calculated by substituting the following formula:

example 1

45.0kg of first deionized water, 1.0kg of potassium oleate, 10.0kg of methanol, 20.0kg of ethanol, 10.0kg of isopropanol, 5.0kg of sodium hydroxide, 2.0kg of nano silicon dioxide with the particle size distribution of 10-20nm, 2.0kg of nano silicon dioxide with the particle size distribution of 20-40nm, 1.0kg of nano silicon dioxide with the particle size distribution of 40-50nm, 5.0kg of vinyltrimethoxysilane, 3.0kg of vinyltriethoxysilane and 2.0kg of vinyltriisopropoxysilane are respectively weighed and added into a reactor, stirring is started, and the reactor is heated to 80 ℃ and kept warm for 20min; adding 100.0kg of second deionized water, 110.0kg of butadiene, 3.0kg of disproportionated potassium abietate, 1.0kg of sodium dodecyl sulfate, 1.0kg of sodium dodecyl benzene sulfonate, 1.0kg of divinylbenzene, 3.0kg of sodium bicarbonate and 1.0kg of potassium persulfate into the reactor to continue the polymerization reaction; sampling and detecting the butadiene conversion rate, namely, the butadiene conversion rate is 1, when the butadiene conversion rate is 1=50.4%, adding 1.0kg of tertiary dodecyl mercaptan into a reaction kettle, and continuing the polymerization reaction; the butadiene conversion was checked by continuing the sampling and was designated as butadiene conversion 2, and 1.0kg of the emulsified silicone oil AFE was added when butadiene conversion 2=97.9% ^TM 0120 stirring, cooling to room temperature, and filtering to obtain core-shell with three layersPolybutadiene latex of structure.

Examples 2 to 5

Examples 2 to 5 are different from example 1 as shown in Table 1, and the other raw materials, experimental conditions and reaction steps are the same as those of example 1.

TABLE 1 differentiation of examples 2-5 from example 1

Comparative example 1

The comparative example 1 was basically identical to the reaction scheme of example 1, except that no nanoscale silica, polymerizable silane coupling agent, and polymerizable crosslinking agent were added, no silicone emulsion was added after the reaction was completed, and the addition amounts and addition timings of other substances and the control of the reaction process were the same as in example 1.

Comparative example 2

Comparative example 2 was substantially identical to the reaction procedure of example 2, except that 1.0kg of vinyltriethoxysilane was not added, and the addition amount and timing of other substances and the control of the reaction procedure were the same as in example 2.

Comparative example 3

Comparative example 3 was substantially identical to the reaction process of example 3, except that the polymerizable crosslinking agent was not added, and the addition amount and timing of other substances and the control of the reaction process were the same as in example 3.

Comparative example 4

Comparative example 4 was substantially identical to the reaction procedure of example 4, except that t-dodecyl mercaptan was not added, and the addition amount and addition timing of other substances and the control of the reaction procedure were the same as in example 4.

Comparative example 5

Comparative example 5 was substantially identical to the reaction process of example 5, except that no nanoscale silica was added, and the addition amount and timing of other substances and the control of the reaction process were the same as in example 5.

The invention was tested by preparing ABS resins from the polybutadiene latices of examples 1-5 and comparative examples 1-5 and injection molding into test bars as follows:

1) ABS graft latex preparation

60kg (on a solids basis) of polybutadiene latex, 120kg of deionized water and 0.001kg of FeSO were added to the reactor ₄ ·7H ₂ O, 0.01kg sodium pyrophosphate and 0.1kg glucose are stirred, a mixed pre-emulsion composed of 0.2kg cumene hydroperoxide, 30kg styrene, 10kg acrylonitrile, 0.5kg tertiary dodecyl mercaptan, 3kg potassium oleate and 10kg deionized water is continuously added into the reactor after the reactor is heated to 70 ℃ and stirred, the continuous feeding time is 3 hours, the reactor is heated to 80 ℃ after the feeding is completed and reacted for 3 hours, the reactor is cooled to normal temperature and stirring is stopped, and the ABS grafted latex is obtained by filtering.

2) Preparation of ABS rubber powder

Adding 1.2kg of concentrated sulfuric acid and 200kg of deionized water into a condensation kettle, stirring to fully dissolve the concentrated sulfuric acid, heating the condensation kettle to 75 ℃, adding 100kg of the ABS grafted latex prepared in the step 1) into the condensation kettle in a continuous feeding mode, continuously feeding for 1 hour, heating the condensation kettle to 90 ℃ after feeding, preserving heat for 1 hour, cooling the condensation kettle to normal temperature, filtering, washing and dehydrating the condensation slurry to obtain ABS wet rubber powder, and drying the ABS wet rubber powder to a water content of <1% by using a fluidized bed dryer at 65 ℃ to obtain the ABS rubber powder.

3) ABS resin preparation, injection molding and performance test

And (2) adopting a double screw extruder, taking SAN resin with the chemical grade of SA 30 of LG as a blending continuous phase, taking the ABS rubber powder prepared in the step (2) as a blending disperse phase, and respectively carrying out blending extrusion and granulation according to the polybutadiene rubber content of 15 percent to obtain the ABS resin.

Preparing various test bars from the ABS resin on an injection molding machine at 190 ℃, and testing according to ASTM-D256, ASTM-D638-2000 and ASTM D790-2000 standards to obtain impact strength, tensile strength and bending strength values of the ABS resin; the abnormal sound prevention performance of the ABS resin is characterized by a noise risk index, the noise risk index is tested according to a German automobile industry standard VDA 230-206 method, the risk coefficient 1-3 is low noise risk, the risk coefficient 4-6 is medium noise risk, and the risk coefficient 7-10 is high noise risk. The correlation evaluation results are shown in Table 2.

TABLE 2 noise risk index of ABS resin and mechanical Property test results

As can be seen from the test results of examples 1 to 5 and comparative examples 1 to 5, the ABS resin prepared using the polybutadiene latex prepared according to the present invention has more excellent anti-abnormal sound effects and also has greatly improved impact strength, tensile strength and flexural strength as compared with the ABS resin prepared using the polybutadiene latex prepared according to the comparative example.

It is apparent that the above examples are given by way of illustration only and are not limiting of the embodiments. Other variations or modifications of the above teachings will be apparent to those of ordinary skill in the art. It is not necessary here nor is it exhaustive of all embodiments. While still being apparent from variations or modifications that may be made by those skilled in the art are within the scope of the invention.

Claims

1. A process for the preparation of polybutadiene latex, characterized by the following steps:

adding first deionized water, a first emulsifier, a water-soluble organic solvent, sodium hydroxide, silicon dioxide and a silane coupling agent into a reactor, starting stirring, heating the reactor, and preserving heat; preferably, the temperature is raised to 55-85 ℃ and kept for 20-120min;

adding second deionized water, butadiene, a second emulsifier, a polymerizable cross-linking agent, an electrolyte and an initiator into a reactor to continue the polymerization reaction;

when the butadiene conversion rate is more than or equal to 50% and less than or equal to 65%, adding a chain transfer agent into the reaction kettle, and continuing the polymerization reaction;

adding emulsified silicone oil when the butadiene conversion rate is more than or equal to 90% and less than or equal to 98%, stirring uniformly, cooling the reactor to normal temperature, and filtering to obtain the polybutadiene latex with a three-layer core-shell structure.

2. The preparation method according to claim 1, wherein the amounts of the respective components in parts by weight are:

40-60 parts of first deionized water, 1-5 parts of first emulsifier, 20-40 parts of water-soluble organic solvent, 1-5 parts of sodium hydroxide, 1-5 parts of silicon dioxide, 1-10 parts of silane coupling agent, 60-100 parts of second deionized water, 110-150 parts of butadiene, 1-5 parts of second emulsifier, 1-5 parts of polymerizable cross-linking agent, 1-5 parts of electrolyte, 1-5 parts of initiator, 1-5 parts of chain transfer agent and 1-5 parts of emulsified silicone oil.

3. The preparation method according to claim 1 or 2, wherein the water-soluble organic solvent is one or more selected from the group consisting of methanol, ethanol, N-propanol, isopropanol, N-butanol, isoamyl alcohol, ethylene glycol, N-dimethylformamide, and tetrahydrofuran; and/or: the silica is nano-scale silica particles, preferably silica particles with a size of 10-50 nm.

4. The method according to claim 1 or 2, wherein the silane coupling agent is one or more of an alkoxysilane containing at least one vinyl group, preferably vinyltrimethoxysilane, vinyltriethoxysilane, vinyltris (β -methoxyethoxy) silane, vinyltriisopropoxysilane, γ -methacryloxypropyl trimethoxysilane.

5. The method of claim 1 or 2, wherein the first emulsifier is identical or different from the second emulsifier, and is selected from one or more of potassium oleate, potassium disproportionated abietate, sodium dodecyl sulfate, sodium dodecyl benzene sulfonate, and sodium dioctyl sulfosuccinate.

6. The preparation method according to claim 1 or 2, characterized in that the polymerizable crosslinking agent is a polymerizable monomer having a multiolefin double bond, preferably one or more of allyl methacrylate, allyl acrylate, divinylbenzene, 1, 4-butanediol dimethacrylate, ethylene glycol dimethacrylate.

7. The preparation method according to claim 1 or 2, wherein the electrolyte is one or more of potassium bicarbonate, potassium carbonate, sodium bicarbonate, sodium carbonate, and sodium tripolyphosphate; and/or:

the initiator is selected from one or more of inorganic peroxide and organic peroxide, preferably one or more of potassium persulfate, sodium persulfate and ammonium persulfate.

8. The process according to claim 1 or 2, wherein the chain transfer agent is t-dodecyl mercaptan.

9. The preparation method according to claim 1 or 2, wherein the emulsified silicone oil is an organosilicon mainly composed of methyl polysiloxane, preferably AFE of the company dakaning ^TM 0120、AFE ^TM 1410、AFE ^TM 3168 and/or BYK from BYK company ^TM 024、BYK ^TM 028, one or more of the following.

10. An ABS resin prepared from the polybutadiene latex prepared by the preparation method according to any one of claims 1 to 9.