Method for producing thermally expandable microspheres and thermally expandable microspheres

文档序号：711680 发布日期：2021-04-16 浏览：53次中文

阅读说明：本技术 热膨胀微球制备方法和热膨胀微球 (Method for producing thermally expandable microspheres and thermally expandable microspheres ) 是由何健平刘志红贺雨晨于 2020-12-23 设计创作，主要内容包括：本发明提供了一种热膨胀微球制备方法和热膨胀微球,属于聚合物功能材料领域,方法包括：将烯属不饱和单体、作为芯剂的挥发性溶剂和引发剂混合得到油相；混合水、金属盐、分散稳定剂、分散稳定助剂、水相阻聚剂以及交联剂,得到水相,交联剂为含有至少一种交联性官能团的化合物；将混合后的油相悬浮在水相中,获得悬浮液；在45-70℃的惰性气氛中,在0.1～0.5MPa的压力下将悬浮溶液聚合反应15～25小时,得到包含热膨胀微球的水性浆料。通过本申请的处理方案,微球发泡的体积可以更大,同时耐收缩性也更好。(The invention provides a preparation method of a thermal expansion microsphere and the thermal expansion microsphere, belonging to the field of polymer functional materials, and the method comprises the following steps: mixing an ethylenically unsaturated monomer, a volatile solvent serving as a core agent and an initiator to obtain an oil phase; mixing water, metal salt, a dispersion stabilizer, a dispersion stabilizing auxiliary agent, a water-phase polymerization inhibitor and a crosslinking agent to obtain a water phase, wherein the crosslinking agent is a compound containing at least one crosslinking functional group; suspending the mixed oil phase in a water phase to obtain a suspension; and carrying out polymerization reaction on the suspension solution for 15-25 hours at the pressure of 0.1-0.5 MPa in an inert atmosphere at the temperature of 45-70 ℃ to obtain the aqueous slurry containing the thermal expansion microspheres. Through the processing scheme of this application, the volume that the microballon was foamed can be bigger, and resistant shrink nature is also better simultaneously.)

1. A method for preparing heat-expandable microspheres, comprising:

mixing an ethylenically unsaturated monomer, a volatile solvent serving as a core agent and an initiator to obtain an oil phase, wherein the ethylenically unsaturated monomer comprises 20-80 wt% of a nitrile monomer, 0-70 wt% of a vinylidene chloride monomer, 5-50 wt% of an acrylate monomer and 0-40 wt% of vinyl acetate, the boiling point of the volatile solvent is not higher than the polymer softening temperature of the ethylenically unsaturated monomer, and the initiator is used for free radical polymerization;

mixing water, metal salt, a dispersion stabilizer, a dispersion stabilizing auxiliary agent, a water-phase polymerization inhibitor and a crosslinking agent to obtain a water phase, wherein the crosslinking agent is a compound containing at least one crosslinking functional group;

suspending the mixed oil phase in the water phase to obtain a suspension;

and carrying out polymerization reaction on the suspension solution for 15-25 hours at the pressure of 0.1-0.5 MPa in an inert atmosphere at the temperature of 45-70 ℃ to obtain the aqueous slurry containing the thermal expansion microspheres.

2. The method for preparing heat-expandable microspheres according to claim 1, wherein the ethylenically unsaturated monomer comprises 30 to 70 wt% of nitrile monomers, 0 to 50 wt% of vinylidene chloride monomers, 20 to 45 wt% of acrylate monomers, and 0 to 20 wt% of vinyl acetate.

3. The method for producing thermally expandable microspheres according to claim 1, wherein the nitrile monomer is at least one of acrylonitrile, methacrylonitrile, α -chloroacrylonitrile, α -ethoxyacrylonitrile, and fumaronitrile.

4. The method of producing heat-expandable microspheres according to claim 1, wherein the acrylic monomer is at least one of methyl acrylate, ethyl acrylate, butyl acrylate, dicyclopentenyl acrylate, methyl methacrylate, ethyl methacrylate, butyl methacrylate, isobornyl methacrylate, and the like.

5. The method of producing heat-expandable microspheres according to claim 1, wherein the initiator is dicetyl peroxydicarbonate, bis (4-t-butylcyclohexyl), peroxydicarbonate, peroxodioctoic acid, dibenzoic acid peroxide, dilauric peroxide, didecanoic acid peroxide, t-butyl peracetate, t-butyl peroxylaurate, t-butyl peroxybenzoate, benzoyl peroxide, t-butyl hydroperoxide, cumene hydroperoxide, ethylcumene peroxide, dicyclohexyl peroxycarbonate, azobisisobutyronitrile, diisopropylhydroxydicarboxylate, 2 ' -azobis ((2, 4-dimethylvaleronitrile), 2 ' -azobis (isobutyronitrile), 1 ' -azobis (cyclohexane-1-carbonitrile), dimethyl 2, at least one of 2-azobis (2-methylpropionate) or 2, 2' -azobis [ 2-methyl-N- (2-hydroxyethyl) -propylene oxide.

6. The method for producing thermally expandable microspheres according to claim 1, wherein the volatile solvent is at least one C3-C15 aliphatic hydrocarbon compound.

7. The method for producing thermally expandable microspheres according to claim 5, wherein the volatile solvent is at least one of butane, isobutane, isopentane, neopentane, n-hexane, heptane, isooctane, octane, and petroleum ether.

8. The method for producing heat-expandable microspheres according to claim 1, wherein the crosslinking agent is divinylbenzene, ethylene glycol di (meth) acrylate, di (ethylene glycol) di (meth) acrylate, triethylene glycol di (meth) acrylate, propylene glycol di (meth) acrylate, 1, 4-butanediol di (meth) acrylate, 1, 6-hexanediol di (meth) acrylate, glycerin di (meth) acrylate, 1, 3-butanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate, 1, 10-decanediol di (meth) acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol hexa (meth) acrylate, triallylformal tri (meth) acrylate, triallyl formal tri (meth) acrylate, or mixtures thereof, At least one of allyl methacrylate, ethylene glycol dimethacrylate, trimethylolpropane tri (meth) acrylate, tributylene glycol di (meth) acrylate, 3-acryloxydiol monoacrylate, triacylglycdehyde, triallyl isocyanate, triallyl isocyanurate, divinyl ether, ethylene glycol divinyl ether, diethylene glycol divinyl ether, triethylene glycol divinyl ether, or tetraethylene glycol divinyl ether.

9. The method for producing heat-expandable microspheres according to claim 1, wherein the metal salt is at least one of sodium chloride, potassium chloride, magnesium chloride, sodium sulfate, potassium sulfate, and magnesium sulfate.

10. The method for producing heat-expandable microspheres according to claim 1, wherein the dispersion stabilizer is at least one of colloidal silica, colloidal calcium carbonate, magnesium hydroxide, calcium phosphate, aluminum hydroxide, iron hydroxide, calcium sulfate, calcium oxalate, calcium carbonate, barium carbonate, magnesium carbonate, and aluminum hydroxide sol.

11. The method for producing heat-expandable microspheres according to claim 1, wherein the dispersion stabilizing aid is a polymer-type dispersion stabilizing aid and is at least one selected from the group consisting of a condensate of diethanolamine and aliphatic dicarboxylic acid, gelatin, tetramethylammonium hydroxide, methylcellulose, dioctyl sulfosuccinate, polyethylene oxide, polyvinyl alcohol, sodium lauryl sulfate, and polyvinylpyrrolidone.

12. The method for producing heat-expandable microspheres according to claim 1, wherein the aqueous-phase polymerization inhibitor is at least one of sodium nitrite, ferric chloride, sodium sulfide, potassium dichromate, and the like.

13. Thermally expandable microspheres, characterized in that they are prepared by the process according to any one of claims 1 to 12.

Technical Field

The invention relates to the field of polymer functional materials, in particular to a preparation method of a thermal expansion microsphere and the thermal expansion microsphere.

Background

The heat expandable microspheres encapsulate the foaming agent in a thermoplastic shell. When the temperature rises, because the boiling point of the foaming agent is lower, the foaming agent is gasified, the internal pressure is increased, the temperature rises, the shell is softened, the microspheres expand under the action of the internal pressure, and the diameter after the expansion can be increased by 2-5 times. In the heating foaming process of the microspheres, along with the gradual gasification of the foaming agent, gas is leaked in the process that the foaming of the microspheres reaches the maximum volume. When excessive gas leakage occurs and the internal pressure generated by the blowing agent is insufficient to support the structure, the microspheres shrink.

Disclosure of Invention

Accordingly, in order to overcome the above-mentioned disadvantages of the prior art, the present invention provides a method for preparing heat-expandable microspheres and heat-expandable microspheres.

In order to achieve the above object, the present invention provides a method for preparing thermally expandable microspheres, comprising: mixing an ethylenically unsaturated monomer, a volatile solvent serving as a core agent and an initiator to obtain an oil phase, wherein the ethylenically unsaturated monomer comprises 20-80 wt% of a nitrile monomer, 0-70 wt% of a vinylidene chloride monomer, 5-50 wt% of an acrylate monomer and 0-40 wt% of vinyl acetate, the boiling point of the volatile solvent is not higher than the polymer softening temperature of the ethylenically unsaturated monomer, and the initiator is used for free radical polymerization; mixing water, metal salt, a dispersion stabilizer, a dispersion stabilizing auxiliary agent, a water-phase polymerization inhibitor and a crosslinking agent to obtain a water phase, wherein the crosslinking agent is a compound containing at least one crosslinking functional group; suspending the mixed oil phase in the water phase to obtain a suspension; and carrying out polymerization reaction on the suspension solution for 15-25 hours at the pressure of 0.1-0.5 MPa in an inert atmosphere at the temperature of 45-70 ℃ to obtain the aqueous slurry containing the thermal expansion microspheres.

In one embodiment, the ethylenically unsaturated monomer comprises, by weight, 30-70% of a nitrile monomer, 0-50% of a vinylidene chloride monomer, 20-45% of an acrylate monomer, and 0-20% of vinyl acetate.

In one embodiment, the nitrile monomer is at least one of acrylonitrile, methacrylonitrile, alpha-chloroacrylonitrile, alpha-ethoxyacrylonitrile, or fumaronitrile.

In one embodiment, the acrylate monomer is at least one of methyl acrylate, ethyl acrylate, butyl acrylate, dicyclopentenyl acrylate, methyl methacrylate, ethyl methacrylate, butyl methacrylate, isobornyl methacrylate, or the like.

In one embodiment, the initiator is dicetyl peroxydicarbonate, bis (4-t-butylcyclohexyl), peroxydicarbonate, dioctanoate peroxide, dibenzoate peroxide, dilaurate peroxide, didecanoic acid peroxide, t-butyl peracetate, t-butyl peroxylaurate, t-butyl peroxybenzoate, benzoyl peroxide, t-butyl hydroperoxide, cumene hydroperoxide, ethylcumene peroxide, dicyclohexyl peroxycarbonate, azobisisobutyronitrile, diisopropylhydroxydicarboxylate, 2 ' -azobis ((2, 4-dimethylvaleronitrile), 2 ' -azobis (isobutyronitrile), 1 ' -azobis (cyclohexane-1-carbonitrile), dimethyl 2,2, -azobis (2-methylpropionate), or 2, at least one of 2' -azobis [ 2-methyl-N- (2-hydroxyethyl) -propylene oxide.

In one embodiment, the volatile solvent is at least one C3-C15 aliphatic hydrocarbon compound.

In one embodiment, the volatile solvent is at least one of butane, isobutane, isopentane, neopentane, n-hexane, heptane, isooctane, octane, petroleum ether.

In one embodiment, the crosslinker is divinylbenzene, ethylene glycol di (meth) acrylate, di (ethylene glycol) di (meth) acrylate, triethylene glycol di (meth) acrylate, propylene glycol di (meth) acrylate, 1, 4-butanediol di (meth) acrylate, 1, 6-hexanediol di (meth) acrylate, glycerol di (meth) acrylate, 1, 3-butanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate, 1, 10-decanediol di (meth) acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol hexa (meth) acrylate, triallylformal tri (meth) acrylate, allyl methacrylate, ethylene glycol dimethacrylate, pentaerythritol tri (meth) acrylate, or mixtures thereof, At least one of trimethylolpropane tri (meth) acrylate, tributylene glycol di (meth) acrylate, 3-acryloxydiol monoacrylate, triacyl formal, triallyl isocyanate, triallyl isocyanurate, divinyl ether, ethylene glycol divinyl ether, diethylene glycol divinyl ether, triethylene glycol divinyl ether, or tetraethylene glycol divinyl ether.

In one embodiment, the metal salt is at least one of sodium chloride, potassium chloride, magnesium chloride, sodium sulfate, potassium sulfate, and magnesium sulfate.

In one embodiment, the dispersion stabilizer is at least one of colloidal silica, colloidal calcium carbonate, magnesium hydroxide, calcium phosphate, aluminum hydroxide, iron hydroxide, calcium sulfate, calcium oxalate, calcium carbonate, barium carbonate, magnesium carbonate, and aluminum hydroxide sol.

In one embodiment, the dispersion stabilizing aid is a polymeric dispersion stabilizing aid, and is at least one of a condensate of diethanolamine and aliphatic dicarboxylic acid, gelatin, tetramethylammonium hydroxide, methylcellulose, dioctyl sulfosuccinate, polyethylene oxide, polyvinyl alcohol, sodium lauryl sulfate, and polyvinylpyrrolidone.

In one embodiment, the aqueous phase polymerization inhibitor is at least one of sodium nitrite, ferric chloride, sodium sulfide, potassium dichromate, and the like.

The invention also provides a thermal expansion microsphere which is characterized by being prepared by any one method.

Compared with the prior art, the invention has the advantages that: the cross-linking agent originally added into the oil phase is added into the water phase, so that after homogenization, the cross-linking agent is mainly distributed on the surface of oil drops, and after reaction is finished, the cross-linked part is mainly concentrated on the surface of the polymer shell, so that on one hand, the microspheres are easier to foam in the heating process due to the small internal cross-linking degree of the polymer shell, and on the other hand, the gas is not easy to leak due to the high cross-linking degree of the surface, so that the foaming volume of the microspheres can be larger, and meanwhile, the shrinkage resistance is also better.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings needed to be used in the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present application, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without creative efforts.

FIG. 1 is a graph showing the comparison of the foaming properties of test tubes of example 1 and comparative example 1 according to the present invention;

FIG. 2 is a graph showing the comparison of the foaming properties of test tubes of example 2 of the present invention and comparative example 2; and

FIG. 3 is a graph showing the comparison of the foaming properties of test tubes of example 3 and comparative example 3 of the present invention.

Detailed Description

The embodiments of the present application will be described in detail below with reference to the accompanying drawings.

The following description of the embodiments of the present application is provided by way of specific examples, and other advantages and effects of the present application will be readily apparent to those skilled in the art from the disclosure herein. It is to be understood that the embodiments described are only a few embodiments of the present application and not all embodiments. The present application is capable of other and different embodiments and its several details are capable of modifications and/or changes in various respects, all without departing from the spirit of the present application. It is to be noted that the features in the following embodiments and examples may be combined with each other without conflict. 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 application.

It is noted that various aspects of the embodiments are described below within the scope of the appended claims. It should be apparent that the aspects described herein may be embodied in a wide variety of forms and that any specific structure and/or function described herein is merely illustrative. Based on the present application, one skilled in the art should appreciate that one aspect described herein may be implemented independently of any other aspects and that two or more of these aspects may be combined in various ways. For example, an apparatus may be implemented and/or a method practiced using any number and aspects set forth herein. Additionally, such an apparatus may be implemented and/or such a method may be practiced using other structure and/or functionality in addition to one or more of the aspects set forth herein.

It should be noted that the drawings provided in the following embodiments are only for illustrating the basic idea of the present application, and the drawings only show the components related to the present application rather than the number, shape and size of the components in actual implementation, and the type, amount and ratio of the components in actual implementation may be changed arbitrarily, and the layout of the components may be more complicated.

In addition, in the following description, specific details are provided to facilitate a thorough understanding of the examples. However, it will be understood by those skilled in the art that the aspects may be practiced without these specific details.

The embodiment of the application provides a preparation method of thermal expansion microspheres, which comprises the following steps:

the method comprises the following steps of mixing an ethylenically unsaturated monomer, a volatile solvent serving as a core agent and an initiator to obtain an oil phase, wherein the ethylenically unsaturated monomer comprises 20-80 wt% of a nitrile monomer, 0-70 wt% of a vinylidene chloride monomer, 5-50 wt% of an acrylate monomer and 0-40 wt% of vinyl acetate, the boiling point of the volatile solvent is not higher than the softening temperature of a polymer of the ethylenically unsaturated monomer, and the initiator is used for free radical polymerization.

Mixing water, metal salt, a dispersion stabilizer, a dispersion stabilizing auxiliary agent, a water-phase polymerization inhibitor and a crosslinking agent to obtain a water phase, wherein the crosslinking agent is a compound containing at least one crosslinking functional group; in one embodiment, when the weight percentage of each component, the cross-linking agent and the initiator in the ethylenically unsaturated monomer is 20-80% of the nitrile monomer, 0-70% of the vinylidene chloride monomer, 5-50% of the acrylate monomer, 0-40% of the vinyl acetate, 0.01-2% of the cross-linking agent and 0.01-1.5% of the initiator.

And step three, suspending the mixed oil phase in a water phase to obtain a suspension.

And step four, carrying out polymerization reaction on the suspension solution for 15-25 hours under the pressure of 0.1-0.5 MPa in an inert atmosphere at the temperature of 45-70 ℃ to obtain the aqueous slurry containing the thermal expansion microspheres.

The nitrile monomer is at least one of acrylonitrile, methacrylonitrile, alpha-chloroacrylonitrile, alpha-ethoxyacrylonitrile or fumaronitrile.

The acrylate monomer is at least one of methyl acrylate, ethyl acrylate, butyl acrylate, dicyclopentenyl acrylate, methyl methacrylate, ethyl methacrylate, butyl methacrylate, isobornyl methacrylate and the like.

The initiator is selected from the group consisting of dicetyl peroxydicarbonate, bis (4-t-butylcyclohexyl), peroxydicarbonate, dioctanoate peroxide, dibenzoate peroxide, dilaurate peroxide, didecanoic acid peroxide, t-butylperacetate, t-butylperaurate, t-butylperoxybenzoate, benzoyl peroxide, t-butyl hydroperoxide, cumene hydroperoxide, ethylcumene peroxide, dicyclohexyl peroxycarbonate, azobisisobutyronitrile, diisopropylhydroxydicarboxylate, 2 '-azobis ((2, 4-dimethylvaleronitrile), 2' -azobis (isobutyronitrile), 1 '-azobis (cyclohexane-1-carbonitrile), dimethyl 2,2, -azobis (2-methylpropionate) and 2, 2' -azobis [ 2-methyl-N- (2-hydroxyethyl) -propylene oxide One of them is less.

In one embodiment, the volatile solvent is at least one C3-C15 aliphatic hydrocarbon compound, preferably, the volatile solvent is at least one C4-C12 straight or branched chain saturated hydrocarbon compound. The volatile solvent is at least one of low molecular weight hydrocarbons such as butane, isobutane, isopentane, neopentane, n-hexane, heptane, isooctane, octane, and petroleum ether, and preferably butane, isobutane, isopentane, n-hexane, petroleum ether, and isooctane. These volatile solvents may be used alone or in combination of two or more, and the content of the volatile solvent may be 5 to 50 wt%, preferably 10 to 50 wt%, more preferably 15 to 40 wt%, and most preferably 20 to 35 wt%, based on 100 wt% of the total weight of the provided thermally expandable microcapsule.

The crosslinking agent is divinylbenzene, ethylene glycol di (meth) acrylate, di (ethylene glycol) di (meth) acrylate, triethylene glycol di (meth) acrylate, propylene glycol di (meth) acrylate, 1, 4-butanediol di (meth) acrylate, 1, 6-hexanediol di (meth) acrylate, glycerin di (meth) acrylate, 1, 3-butanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate, 1, 10-decanediol di (meth) acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol hexa (meth) acrylate, triallylformal tri (meth) acrylate, allyl methacrylate, ethylene glycol dimethacrylate, trimethylolpropane tri (meth) acrylate, propylene glycol di (, At least one of tributylene glycol di (meth) acrylate, 3-acryloxydiol monoacrylate, triacyl formal, triallyl isocyanate, triallyl isocyanurate, divinyl ether, ethylene glycol divinyl ether, diethylene glycol divinyl ether, triethylene glycol divinyl ether, or tetraethylene glycol divinyl ether.

The metal salt is at least one of sodium chloride, potassium chloride, magnesium chloride, sodium sulfate, potassium sulfate and magnesium sulfate.

The dispersion stabilizer is at least one of colloidal silica, colloidal calcium carbonate, magnesium hydroxide, calcium phosphate, aluminum hydroxide, ferric hydroxide, calcium sulfate, calcium oxalate, calcium carbonate, barium carbonate, magnesium carbonate and aluminum hydroxide sol. The dispersion stabilizer may be a solid or a colloid.

The dispersion stabilizing assistant is a polymer type dispersion stabilizing assistant, and can be at least one of condensation product of diethanolamine and aliphatic dicarboxylic acid, gelatin, tetramethylammonium hydroxide, methylcellulose, dioctyl sulfosuccinate, polyethylene oxide, polyvinyl alcohol, sodium lauryl sulfate, and polyvinylpyrrolidone.

The aqueous phase polymerization inhibitor may be at least one of sodium nitrite, ferric chloride, sodium sulfide, potassium dichromate, and the like.

According to the method, the aqueous slurry can be prepared, and can be directly used for the subsequent use of the microspheres, for example, the aqueous slurry can be used in industries such as papermaking, automobile chassis, coating and the like. Microspheres can also be prepared to give dispersions, which can be dewatered by any conventional method, such as bed filtration, pressure filtration, leaf filtration, belt filtration, or centrifugation, to give a wet cake; and the filter cake can be dried by any conventional method such as spray drying, rack drying, tunnel drying, rotary drying, drum drying, through-air drying, turbo rack drying, disc drying, fluidized bed drying, or the like to obtain the thermally expandable microspheres.

According to the preparation method of the thermal expansion microsphere, the cross-linking agent originally added into the oil phase is added into the water phase, so that after homogenization, the cross-linking agent is mainly distributed on the surface of oil drops, and after reaction is finished, the cross-linked part is mainly concentrated on the surface of the polymer shell, therefore, on one hand, the microsphere is easier to foam in the heating process due to the small internal cross-linking degree of the polymer shell, and on the other hand, the foaming volume of the microsphere is larger and the shrinkage resistance is better due to the fact that the gas is not easy to leak due to the high surface cross-linking degree.

In one embodiment, the ethylenically unsaturated monomer comprises 30-70 wt% of nitrile monomer, 0-50 wt% of vinylidene chloride monomer, 20-45 wt% of acrylate monomer and 0-20 wt% of vinyl acetate.

Example 1

100 g of acrylonitrile, 40 g of methyl methacrylate, 57 g of methyl acrylate, 2.2 g of dicyclohexyl carbonate diperoxide and 60 g of isobutane were mixed to obtain an oil phase for suspension polymerization.

In 600 g of ion-exchanged water, 23 g of sodium chloride, 10 g (amount of active ingredient: 25% by weight) of colloidal silica, 0.2 g of sodium lauryl sulfate, 0.1 g of polyvinylpyrrolidone and 0.01 g of sodium nitrite, and 0.8 g of trimethylolpropane trimethacrylate were added, and then the pH was adjusted to 2.4, and uniformly mixed to give an aqueous phase.