CN111004347B

CN111004347B - Low-ammonia-release-amount water-based emulsion and preparation method and application thereof

Info

Publication number: CN111004347B
Application number: CN201911321223.7A
Authority: CN
Inventors: 侯雷刚; 王智英; 舒国玉; 赵以兵; 乔义涛
Original assignee: Wanhua Chemical Group Co Ltd; Wanhua Chemical Ningbo Co Ltd; Wanhua Chemical Guangdong Co Ltd
Current assignee: Wanhua Chemical Group Co Ltd; Wanhua Chemical Ningbo Co Ltd; Wanhua Chemical Guangdong Co Ltd
Priority date: 2019-12-20
Filing date: 2019-12-20
Publication date: 2022-04-22
Anticipated expiration: 2039-12-20
Also published as: CN111004347A

Abstract

The invention discloses a water-based emulsion with low ammonia release amount, and a preparation method and application thereof. The water-based emulsion comprises the following raw material components in parts by weight: hard monomer: 240 portion and 330 portions; soft monomer: 632 and 746 parts; functional monomer: 10-30 parts; polymerizing the stabilizing monomer: 4-14 parts; and an emulsifier: 8.1-24 parts; dispersing agent: 0-4 parts. The waterproof emulsion prepared by the invention not only has excellent mechanical property, but also has the characteristic of low ammonia release amount.

Description

Low-ammonia-release-amount water-based emulsion and preparation method and application thereof

The technical field is as follows:

the invention relates to a water-based emulsion with low ammonia release amount, a preparation method and application thereof, belonging to the fields of acrylic emulsion synthesis and architectural coatings.

Background art:

the polymer cement (JS) waterproof coating is widely applied to places such as bathrooms, basements, water pools and the like due to good tensile strength, crack resistance, waterproof performance and the like. Common emulsions used to formulate JS water-resistant coatings are typically obtained using copolymerization of acrylate monomers with (meth) acrylamide. The acrylamide unit in the polymer is beneficial to mixing of the emulsion and the cement powder, so that the coagulation of cement is delayed, the preparation and construction of the JS waterproof coating are facilitated, and the obtained JS waterproof coating has good cracking resistance.

However, after the waterproof emulsion containing acrylamide is mixed with the cement powder with strong alkalinity, the acrylamide can be decomposed to release ammonia, so that a sharp smell is generated, and the construction workers are greatly damaged. With the concern of people on the health of people, the requirement on the environmental protection level of materials is higher and higher. Therefore, the development of JS waterproof emulsion with low ammonia or even zero ammonia is urgent.

CN106715491A discloses the preparation of a polyacrylate copolymer dispersion for flexible cementitious waterproofing coatings. The polyacrylate dispersion is obtained by copolymerizing styrene, (meth) acrylate, hydroxyalkyl (meth) acrylate and some functional monomers. However, this patent requires the introduction of foreign seeds, resulting in a cumbersome production process.

CN105949381A discloses an amine-free waterproof emulsion and a preparation method thereof, wherein the waterproof emulsion is obtained by copolymerizing styrene, acrylate monomer, phosphate monomer, organosilicon monomer and the like, and the mechanical property of a waterproof coating is improved by improving the compactness of a paint film by utilizing the interaction among functional monomers. However, the patent uses APEO type emulsifier, which is a great harm to the environment. At the same time, the molecular weight of the resulting emulsion polymer is reduced due to the use of a chain transfer agent. To compensate for this drawback, a large amount of crosslinking monomer such as PAM-100, vinyltriethoxysilane, needs to be added, resulting in a high raw material cost.

The invention content is as follows:

compared with the waterproof coating prepared by the traditional waterproof emulsion, the waterproof coating prepared by the emulsion has the advantages that the irritant ammonia odor is obviously reduced, and the waterproof coating has excellent tensile strength and elongation at break.

The invention also aims to provide a preparation method and application of the aqueous emulsion with low ammonia release amount.

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

the water-based waterproof emulsion is prepared from the following raw materials in parts by mass:

hard monomer 240 and 330; preferably 250-

Soft monomer: 632 and 746 parts; preferably 672-734 parts

Functional monomer: 10-30 parts; preferably 12 to 20 parts

Polymerizing the stabilizing monomer: 4-14 parts; preferably 6 to 11 parts

Emulsifier: 8.1-24 parts; preferably 11.1 to 16.2 parts

Dispersing agent: 0 to 4 parts, preferably 1.2 to 2.8 parts

In the present invention, the hard monomer is one or more of the following substances: styrene, methyl methacrylate, t-butyl acrylate, and vinyl versatate (VV-9), preferably methyl methacrylate and styrene, and more preferably styrene.

In the present invention, the soft monomer is (meth) acrylic acid C_4-8One or more of the alkyl esters, preferably butyl acrylate and/or isooctyl acrylate, more preferably butyl acrylate.

In the invention, the functional monomer is one or more of the following substances: n-allyl methacrylamide, N-allyl acrylamide, preferably N-allyl acrylamide.

In the invention, the polymerization stable monomer is one or two of sodium p-styrene sulfonate and sodium 3-allyloxy-2-hydroxy-1-propanesulfonate, and preferably sodium 3-allyloxy-2-hydroxy-1-propanesulfonate.

In the invention, the emulsifier is one or more of the following substances: sodium dodecyl sulfate, sodium dodecyl benzene sulfonate, alkyl polyoxyethylene ether sulfate, sodium sulfosuccinate diester, alkyl polyoxyethylene ether, and allyl alkyl polyoxyethylene ether sulfate, preferably sodium dodecyl benzene sulfonate and/or alkyl polyoxyethylene ether sulfate.

In the invention, the dispersant is an anionic polycarboxylic acid dispersant, such as SN-5040 of Santanoploceae, preferably, the aqueous emulsion with low ammonia release amount further comprises a polymerization initiator, and the addition amount of the polymerization initiator is 3-8 parts.

In the present invention, the aqueous waterproof emulsion can be obtained by initiating polymerization by a non-ammonium polymerization initiator known in the art, for example, potassium persulfate, sodium persulfate, and an oxidation-reduction initiator such as t-butyl hydroperoxide-isoascorbic acid, t-butyl hydroperoxide-sodium metabisulfite, t-amyl hydroperoxide-isoascorbic acid, etc., with sodium persulfate being preferred.

In the present invention, in order to adjust the pH of the resulting aqueous waterproof emulsion, the aqueous waterproof emulsion further comprises a pH adjuster, and the pH adjuster may be an aqueous alkali metal hydroxide solution, for example, an aqueous sodium hydroxide solution or an aqueous potassium hydroxide solution. The pH value does not influence the performance of the emulsion, and a small amount of the pH value is added to adjust the pH value of the emulsion to the required pH value, so the requirement of quantity is not made.

The second aspect of the present invention provides a method for preparing the above waterproof emulsion, comprising the steps of:

(1) adding a functional monomer, water, a partially polymerized stable monomer, an emulsifier, a soft monomer and a hard monomer into a pre-emulsification bottle, and stirring until a stable milky pre-emulsion is formed;

(2) adding water and the residual polymerization stable monomer into a reaction bottle, heating to the polymerization reaction temperature, preferably 80-90 ℃, and then adding part of the pre-emulsion prepared in the step (1);

(3) adding an initiator accounting for 18.5-50% of the total mass of the initiator into the reaction bottle, and synchronously dropwise adding the rest pre-emulsion and the rest initiator into the reaction bottle after 15-30 min.

In the present invention, after the polymerization reaction is completed, a post-elimination initiator, preferably a conventional oxidation-reduction initiator, is added to the reaction flask to post-eliminate the unreacted monomers in the emulsion and reduce the content of the unreacted monomers to reduce the odor of the emulsion.

In the present invention, the reaction temperature of the post elimination reaction is preferably 70 to 80 ℃.

The oxidant in the post-elimination initiator is selected from tert-butyl hydroperoxide (t-BHP) and hydrogen peroxide (H)₂O₂) T-amyl hydroperoxide (t-AHP), and the like, and the reducing agent is selected from isoascorbic acid (IAA), sodium metabisulfite, sodium bisulfite, FF6M, and the like.

The method comprises the steps of synchronously dripping an aqueous solution of an oxidant and an aqueous solution of a reducing agent, then optionally cooling to 40-45 ℃, adding a pH regulator and a dispersing agent, and filtering to obtain the aqueous emulsion with low ammonia release amount.

In the present invention, the amount of water added in step (1) is 270 parts, preferably 250 parts and 265 parts.

In the present invention, the addition amount of the polymerization stable monomer in the step (1) is 0 to 43%, preferably 27.3 to 33.3% by mass of the total mass of the polymerization stable monomer.

In the present invention, the amount of the pre-emulsion added in the step (2) is 1.5 to 6.5%, preferably 2 to 6%, of the total mass of the pre-emulsion prepared in the step (1).

Preferably, the residual pre-emulsion and the residual initiator in step (3) are added dropwise in a time period of 3h to 5 h.

In a preferred embodiment of the present invention, the oxidizing agent used for reducing the residual monomers in the emulsion is tert-butyl hydroperoxide, the reducing agent is isoascorbic acid, and the reaction temperature is 75 ℃.

Preferably, the addition amount of the oxidizing agent and the reducing agent in the post-elimination initiator is 0.25-0.5% and 0.15-0.3% of the total mass of all the monomers, respectively.

All monomers include hard monomers, soft monomers, functional monomers and polymerization stable monomers.

The third aspect of the invention provides the application of the waterproof emulsion, namely the application of the waterproof emulsion or the waterproof emulsion obtained by the preparation method in the preparation of waterproof paint and a product obtained by the preparation method.

The low ammonia release amount aqueous emulsion provided by the invention has the following advantages:

(1) according to the invention, N-allyl methacrylamide and/or N-allyl acrylamide are introduced into the polymer, and N-H is contained in the N-allyl (methyl) acrylamide, so that a hydrogen bond action can be generated between N-H and a hydrogen bond action can be generated with-OH in a polymerization stable monomer, thereby improving the cohesion between emulsion polymers, improving the mechanical property of the waterproof coating, and enabling the prepared waterproof coating to have excellent tensile strength and elongation at break.

(2) The addition of the initiator is eliminated, so that the use amount of polymerization initiators such as sodium persulfate, potassium persulfate and the like can be reduced, and the water resistance of the obtained emulsion is improved.

(3) The N-allyl (methyl) acrylamide used in the invention has allyl which can be copolymerized with other monomers, and under the alkaline condition, after amido bonds are broken, the amido groups are still fixed on the polymer, no volatile matter is generated, and the generation of pungent odor is reduced.

(4) The N-allyl (methyl) acrylamide is adopted, so that the emulsion has a certain crosslinking effect, and the molecular weight of the emulsion can be improved, so that the mechanical property of the waterproof coating is improved.

(5) The polymerization stable monomer adopted by the invention is helpful for emulsion synthesis, and can form ionic bonding with powder in the waterproof coating, so that the strength of the waterproof coating is improved.

Detailed Description

The following examples further illustrate the invention but are not intended to limit the invention thereto.

The starting materials and sources used in the examples are shown in Table 1.

TABLE 1

For short	Compound (I)	Manufacturer of the product
			St	Styrene (meth) acrylic acid ester	Qilu petrochemical
BA	Acrylic acid butyl ester	Wanhua Chemical Group Co., Ltd.
			EHA	Acrylic acid isooctyl ester	Wanhua Chemical Group Co., Ltd.
MMA	Methacrylic acid methyl ester	Wanhua Chemical Group Co., Ltd.
			SSS	Sodium p-styrene sulfonate	Zibo xing-Chi chemical Co., Ltd
COPS-1	3-allyloxy-2-hydroxy-1-propanesulfonic acid sodium salt	Soervi chemical group
				N-allyl acrylamide	Sigma Aldrich China
DS-4AP	Sodium dodecyl benzene sulfonate	Soervi chemical group
			FES-77	Alkyl polyoxyethylene ether sulfate	BASF CHINA Co.,Ltd.
SN-5040	Sodium polycarboxylate dispersants	Saint Nenopol (Shanghai) trade Co Ltd

COPS-1: the effective content is 40%

DS-4 AP: the effective content is 22.5%

FES-77: the effective content is 30%

SN-5040: the effective content is 40%

Example 1

(1) Sequentially adding 10 parts of N-allyl acrylamide, 264.4 parts of deionized water, 36 parts of DS-4AP, 240 parts of St and 746 parts of BA into a pre-emulsifying kettle, and stirring to obtain a stable pre-emulsion;

(2) adding 10 parts of COPS-1 and 330 parts of deionized water into a reaction kettle, heating to 85 ℃, and adding 25.93 parts of the pre-emulsion prepared in the step (1);

(3) and (3) adding an aqueous solution formed by 1.5 parts of sodium persulfate and 15 parts of deionized water into the reaction kettle, and synchronously and respectively dropwise adding the pre-emulsion remained in the step (1) and an aqueous solution formed by 1.5 parts of sodium persulfate and 75 parts of deionized water after 20 min. The pre-emulsion is dripped for about 240min, and the initiator aqueous solution is dripped for about 250 min. And keeping the temperature for 30min after the dropping of the initiator aqueous solution is finished.

(4) Cooling the reaction liquid to 75 ℃, synchronously and respectively dropwise adding an aqueous solution formed by 5 parts of tert-butyl hydroperoxide (70%) and 24 parts of deionized water and an aqueous solution formed by 3 parts of isoascorbic acid and 15 parts of water, dropwise adding for about 25min, and then continuously preserving the heat for 20 min.

(5) The reaction solution was cooled to 40 ℃ or lower, 18 parts of NaOH (10%) aqueous solution and 10 parts of SN-5040 were added, and then filtered to obtain a flexible waterproof emulsion.

Examples 2 to 5 the same procedure as in example 1 was followed, except that the amount and kind of the raw materials were changed as shown in Table 2.

TABLE 2

Comparative example 1

(1) Adding 255 parts of deionized water, 2 parts of SSS, 36 parts of DS-4AP, 20 parts of FES-77, 265 parts of St, 627 parts of BA and 100 parts of EHA into a pre-emulsifying kettle, and stirring to obtain a stable pre-emulsion;

(2) adding 15 parts of COPS-1 and 330 parts of deionized water into a reaction kettle, heating to 85 ℃, and adding 52.12 parts of the pre-emulsion prepared in the step (1);

(3) and (3) adding an aqueous solution formed by 1.5 parts of sodium persulfate and 15 parts of deionized water into the reaction kettle, and synchronously and respectively dropwise adding the pre-emulsion remained in the step (1) and an aqueous solution formed by 3.5 parts of sodium persulfate and 75 parts of deionized water after 20 min. The pre-emulsion is dripped for about 240min, and the initiator aqueous solution is dripped for about 250 min. And keeping the temperature for 30min after the dropping of the initiator aqueous solution is finished.

(4) Cooling the reaction liquid to 75 ℃, synchronously and respectively dropwise adding an aqueous solution formed by 3.6 parts of tert-butyl hydroperoxide (70%) and 24 parts of deionized water and an aqueous solution formed by 1.8 parts of isoascorbic acid and 15 parts of water, dropwise adding for about 25min, and then continuously preserving the temperature for 20 min.

(5) The reaction solution was cooled to 40 ℃ or lower, 18 parts of NaOH (10%) aqueous solution and 5 parts of SN-5040 were added, followed by filtration to obtain a flexible waterproof emulsion.

Comparative example 2

Comparative example 2 the same preparation as in comparative example 1 was carried out using the starting materials shown in Table 2.

The emulsion parameters for flexible waterproof coating materials prepared in examples 1 to 5 of the present invention and comparative examples 1 to 2 are shown in Table 3.

TABLE 3

	Example 1	Example 2	Example 3	Example 4	Example 5	Comparative example 1	Comparative example 2
								Particle size of emulsion	297	294	301	305	317	298	320
Index of particle size distribution	0.035	0.03	0.026	0.033	0.057	0.032	0.022
								Viscosity (cps)	720	670	800	470	300	750	920
pH value	7.6	7.6	7.4	7.5	7.2	7.5	7.3
								Solid content (%)	56.4	56.5	56.4	56.3	55.8	56.4	56.4

The general method comprises the following steps:

the liquid component and the powder component were mixed according to the formulation shown in table 4 and stirred for 3-5 min. The obtained flexible waterproof coating material was scraped on a polytetrafluoroethylene plate by a blade coater to obtain a flexible waterproof coating material film of 1.5 mm. The film was cured at 23 ℃ at 50% relative humidity for 4 days and then in an oven at 40 ℃ for 2 days. The film was then cooled to room temperature in a desiccator and tested for performance.

TABLE 4 Flexible Water-repellent coating compositions

The tensile strength and elongation at break of seven flexible water repellent coating films prepared respectively from examples 1 to 5, comparative example 1 and comparative example 2 were measured as specified in GB/T23445-2009 II. The ammonia content of the flexible waterproof emulsions obtained in examples 1 to 5 and comparative examples 1 and 2 was measured in accordance with the specification of JC 1066-.

Test results

The mechanical properties and the amount of ammonia released measured for the examples and comparative examples are summarized in table 5.

TABLE 5

Test specimen	Example 1	Example 2	Example 3	Example 4	Example 5	Comparative example 1	Comparative example 2
								Tensile Strength (MPa)	1.8	2	2.3	2.4	2.7	1.2	2.2
Elongation at Break (%)	93	100	107	109	103	66	116
								Ammonia content (ppm)	26	30	27	25	25	27	652

From the results shown in table 5, it can be seen that the flexible waterproof coating prepared from the flexible waterproof emulsion prepared by the invention has mechanical properties equivalent to those of the flexible waterproof coating prepared from the traditional flexible waterproof emulsion prepared from acrylamide, and the environmental protection effect is better because the content of ammonia is obviously lower than that of the flexible waterproof coating prepared from acrylamide.

Claims

1. The aqueous emulsion with low ammonia release amount is characterized by being prepared from the following raw materials in parts by weight based on the dry weight of the used materials:

hard monomer: 240 portion and 330 portions;

soft monomer: 632 and 746 parts;

functional monomer: 10-30 parts;

polymerizing the stabilizing monomer: 4-14 parts;

emulsifier: 8.1-24 parts;

dispersing agent: 0-4 parts of a solvent;

the functional monomer is N-allyl methacrylamide and/or N-allyl acrylamide;

the hard monomer is methyl methacrylate and/or styrene;

the soft monomer is butyl acrylate and/or isooctyl acrylate;

the polymerization stable monomer is sodium p-styrene sulfonate and/or 3-allyloxy-2-hydroxy-1-sodium propane sulfonate.

2. The aqueous emulsion with low ammonia release amount according to claim 1, which is prepared from the following raw materials in parts by weight based on the dry weight of the used materials:

hard monomer: 250 and 310 parts;

soft monomer: 672 and 734 parts;

functional monomer: 12-20 parts;

polymerizing the stabilizing monomer: 6-11 parts;

emulsifier: 11.1-16.2 parts;

dispersing agent: 1.2 to 2.8 portions.

3. The aqueous emulsion with low ammonia release according to claim 1, wherein the hard monomer is styrene.

4. The aqueous emulsion with low ammonia release according to claim 1, wherein the soft monomer is butyl acrylate.

5. The aqueous emulsion with low ammonia release amount according to claim 1, wherein the emulsifier is one or more of sodium dodecyl sulfate, sodium dodecyl benzene sulfonate, alkyl polyoxyethylene ether sulfate, sodium sulfosuccinate diester, alkyl polyoxyethylene ether and allyl alkyl polyoxyethylene ether sulfate.

6. The aqueous emulsion with low ammonia release according to claim 5, wherein the emulsifier is sodium dodecyl benzene sulfonate and/or alkyl polyoxyethylene ether sulfate.

7. The aqueous emulsion with low ammonia release according to claim 1, wherein the dispersant is an anionic dispersant.

8. The aqueous emulsion with low ammonia release amount according to claim 1, characterized in that the aqueous emulsion with low ammonia release amount further comprises a polymerization initiator, and the addition amount of the polymerization initiator is 3-8 parts.

9. The aqueous emulsion having a low ammonia release amount according to claim 8, wherein the polymerization initiator is a non-ammonium polymerization initiator.

10. The aqueous emulsion with low ammonia release according to claim 9, wherein the polymerization initiator is potassium persulfate, sodium persulfate, or an oxidation-reduction type initiator.

11. The aqueous emulsion with low ammonia release according to claim 10, wherein the oxidation-reduction initiator is t-butyl hydroperoxide-isoascorbic acid, t-butyl hydroperoxide-sodium metabisulfite or t-amyl hydroperoxide-isoascorbic acid.

12. The aqueous emulsion with low ammonia release according to claim 10, wherein the polymerization initiator is sodium persulfate.

13. The low ammonia release aqueous emulsion according to claim 1, further comprising a pH adjusting agent.

14. A process for preparing an aqueous emulsion according to any one of claims 1 to 13, comprising the steps of:

(1) mixing water, functional monomer, partial polymerization stable monomer, emulsifier, soft monomer and hard monomer, and stirring to form stable pre-emulsion;

(2) adding water and the residual polymerization stable monomer into a reaction bottle, heating to the polymerization reaction temperature, and adding part of the pre-emulsion prepared in the step (1);

(3) and (3) adding a part of initiator aqueous solution into the reaction bottle, and synchronously dropwise adding the rest pre-emulsion and the rest initiator into the reaction bottle after 15-30 min.

15. The method according to claim 14, wherein the polymerization temperature in the step (2) is 80 to 90 ℃.

16. The process according to claim 14, wherein the pre-emulsion in step (2) is added in an amount of 1.5 to 6.5% based on the total mass of the pre-emulsion prepared in step (1).

17. The process according to claim 16, wherein the pre-emulsion in step (2) is added in an amount of 2 to 6% by mass based on the total mass of the pre-emulsion prepared in step (1).

18. The process according to claim 14, wherein the pre-emulsion remaining in step (3) and the initiator remaining are added dropwise over a period of 3 to 5 hours.

19. The process of claim 14, wherein the initiator initially added in step (3) is 18.5 to 50% of the total mass of the initiator.

20. The method of claim 14, wherein the amount of the polymeric stabilizing monomer added in step (1) is 0 to 43% of the total mass of the polymeric stabilizing monomer.

21. The method of claim 20, wherein the amount of the polymeric stabilizing monomer added in step (1) is 27.3 to 33.3% of the total mass of the polymeric stabilizing monomer.

22. The method as claimed in claim 14, wherein after the reaction in step (3) is completed, the post-initiator is added to the reaction flask to reduce the content of unreacted monomers in the emulsion, and then optionally, the temperature is reduced to 40-45 ℃ and pH regulator and dispersant are added, and the mixture is filtered to obtain the aqueous emulsion.

23. The method of claim 22, wherein the post-elimination initiator is a redox-type initiator.

24. The method as claimed in claim 23, wherein the oxidizing agent in the post-elimination initiator is selected from t-butyl hydroperoxide, hydrogen peroxide, t-amyl hydroperoxide, and the reducing agent is selected from isoascorbic acid, sodium metabisulfite, sodium bisulfite, FF6M, wherein the amount of the oxidizing agent added is 0.25-0.5% of the total mass of all monomers, and the amount of the reducing agent added is 0.15-0.3% of the total mass of all monomers.

25. Use of an aqueous emulsion according to any one of claims 1 to 13 or an aqueous emulsion obtained by the preparation process according to any one of claims 14 to 24 for the preparation of a water-repellent coating.