CN112708004A

CN112708004A - Vinyl acetate-ethylene copolymer emulsion and preparation method thereof

Info

Publication number: CN112708004A
Application number: CN201911019351.6A
Authority: CN
Inventors: 曹勇; 刘晶晶; 吴江红; 张波; 宁志明
Original assignee: Chongqing Chuanwei Technology Co ltd; China Petroleum and Chemical Corp; Sinopec Chongqing Chuanwei Chemical Co Ltd
Current assignee: Chongqing Chuanwei Technology Co ltd; China Petroleum and Chemical Corp; Sinopec Chongqing Chuanwei Chemical Co Ltd
Priority date: 2019-10-24
Filing date: 2019-10-24
Publication date: 2021-04-27
Anticipated expiration: 2039-10-24
Also published as: CN112708004B

Abstract

The invention belongs to the technical field of vinyl acetate copolymers, and particularly relates to vinyl acetate-ethylene copolymer emulsion. The stripping strength of the vinyl acetate-ethylene copolymer emulsion is 0.338-0.387N/mm. The adhesive property of the vinyl acetate-ethylene copolymer emulsion is obviously improved.

Description

Vinyl acetate-ethylene copolymer emulsion and preparation method thereof

Technical Field

The invention belongs to the technical field of vinyl acetate copolymers, and particularly relates to vinyl acetate-ethylene copolymer emulsion and a preparation method thereof.

Background

VAE emulsion (vinyl acetate-ethylene copolymer) emulsion was first commercialized in the middle of the 60 s of the 20 th century by Air Products Ins, the american Air de Products company, which was originally used for paper coating, the manufacture of latex paints and adhesives ("the development of VAE emulsions", bang et al, china adhesives, 14, 2 nd vol.2005, page 46, published 2005, 12 th and 31 th).

Vinyl acetate-ethylene copolymer emulsion is a high molecular emulsion (VAE emulsion environmental protection research progress, tension change, medium and small-sized enterprise management and science and technology, 2017, No. 8, page 92, published day 2017, 04 and 24 days; VAE emulsion research progress, Wangwanting, Chinese adhesive, 2010, No. 19, No. 8, page 59, published day 2010, 08 and 31 days) which is prepared by using vinyl acetate and ethylene as basic raw materials and adopting an emulsion polymerization method. Due to the introduction of the ethylene monomer, compared with a polyvinyl acetate emulsion, the number of acetate groups on the molecular chain of the VAE emulsion is reduced, so that the intercommunication among macromolecules is reduced, the mobility among the molecules is increased, the interaction in the molecules is also reduced, and the macromolecular chain is softened; and because the ethylene monomer and the vinyl acetate monomer are copolymerized into a whole, the polymer becomes permanent plasticization, and compared with an additional plasticizer, the defects that a low-molecular plasticizer is easy to migrate, permeate, volatilize and the like are overcome. Therefore, the VAE emulsion has special properties, such as lower film forming temperature, lower surface tension and the like, compared with the polyvinyl acetate emulsion, can bond various substrates which are difficult to bond with the polyvinyl acetate emulsion, is stable to oxygen, ozone, ultraviolet rays and the like, and has better water resistance, alkali resistance, freeze-thaw resistance, acid resistance, storage stability and the like than the polyvinyl acetate emulsion ("the technical development and application of the VAE emulsion", faithful to the English, modern chemical industry, volume 9, 5 th of 1989, page 26, published as 12 and 31 days of 1989). Therefore, the vinyl acetate-ethylene copolymer emulsion is widely applied to the fields of buildings, building materials, cigarette adhesive, waterproof coating, paper products, wood, clothes, furniture, shoes, handbags, pressure-sensitive adhesives, fabrics, carpets, coatings, artware processing, three-dimensional oil paintings, air filters and the like ("VAE emulsion environmental protection research progress", Zhang Hua, medium and small-sized enterprise management and science and technology, No. 8 in 2017, No. 92, published No. 2017, 24 in 04 and month; "VAE emulsion technical progress and application", loyalty, modern chemical industry, No. 9, No. 5 in 1989, No. 26, No. 12 in 1989, No. 31 in 20159, "application and market development status of VAE emulsion in China", Zhenjiang, Shanghai chemical industry, No. 40, No. 8 in 2015, No. 47, and published No. 2015, 08 in 2015 and No. 31).

However, the conventional vinyl acetate-ethylene copolymer emulsion has disadvantages of poor affinity to a low surface tension substrate, low adhesion, and the like, since it uses vinyl acetate as a main monomer. In recent years, the industries such as textile, packaging, wood processing and the like in China are changed greatly, and the composite materials are used in large quantities, so that higher requirements are put forward on the bonding performance of the adhesive. However, the conventional carboxyl-modified vinyl acetate-ethylene copolymer emulsion is poor in adhesion performance, and often has a peel strength (peel strength is the maximum force required for width peeling of materials bonded together from a contact surface, specifically, the peel strength of a composite of a polyester fabric and a nonwoven fabric) of about 0.2N/mm, and the adhesion strength between substrates is low, and therefore, the adhesive strength is not satisfactory when used in textile, packaging, woodworking and the like.

Disclosure of Invention

In view of the above, an object of the present invention is to provide a vinyl acetate-ethylene copolymer emulsion having excellent adhesion properties.

The parts are parts by mass unless otherwise specified.

In order to achieve the purpose, the technical scheme of the invention is as follows:

the preparation method of the vinyl acetate-ethylene copolymer emulsion is prepared from raw materials including a monomer, an emulsifying system, an initiator, a reducing agent, a pH regulator and water, wherein the monomer comprises alcohols with the carbon atom number of 2-8 and the number of alcoholic hydroxyl groups of more than or equal to 2.

Further, the alcohol is 1-3 of ethylene glycol, glycerol and pentaerythritol.

Further, the alcohol is ethylene glycol or glycerol.

Further, the monomer includes a carboxylic acid monomer.

Further, the carboxylic acid monomer is acrylic acid or acrylic acid derivatives or a combination thereof.

Further, the acrylic acid derivative refers to methacrylic acid.

Further, the monomers also include vinyl acetate and ethylene.

Further, the monomer comprises 44.0-52.0 parts of vinyl acetate, a proper amount of ethylene, 5.2-5.7 parts of carboxylic acid monomer and 1.5-3.5 parts of alcohol by mass.

Further, the emulsifying system is a protective colloid or an emulsifier or a combination thereof.

Further, the protective colloid is one or a combination of several of polyvinyl alcohol with the polymerization degree of 500-2400 and the alcoholysis degree of 88-99%.

Further, the emulsifier is octyl phenol polyoxyethylene ether with 10 or 30 ethoxy groups or a combination thereof.

Further, the initiator is a peroxide initiator.

Further, the peroxide initiator is 1-4 of hydrogen peroxide, potassium persulfate, ammonium persulfate and tert-butyl hydroperoxide.

Further, the reducing agent is 1-6 of ascorbic acid, sodium erythorbate, tartaric acid, sodium sulfite, sodium formaldehyde sulfoxylate and sodium metabisulfite.

Further, the pH regulator is 1-4 of sodium acetate, sodium bicarbonate, sodium carbonate and disodium hydrogen phosphate.

Further, the proportioning relation is as follows by mass parts: 49.2-57.7 parts of vinyl acetate, a proper amount of ethylene, 5.2-5.7 parts of carboxylic acid monomer, 2.4-3.0 parts of an emulsifying system, 0.06-0.32 part of an initiator, 0.017-0.13 part of a reducing agent, 1.5-3.5 parts of alcohols, 0.04-0.13 part of a pH regulator and 40.0-45.0 parts of water.

Further, the vinyl acetate-vinyl alcohol copolymer emulsion is prepared by adopting a semi-continuous emulsion polymerization method.

Further, the preparation method comprises the following steps: raw material preparation and feeding production, wherein the feeding production process specifically comprises the following steps:

replacing the reaction kettle with inert gas, then adding water and polyvinyl alcohol into the reaction kettle, then sequentially adding an emulsifier, a reducing agent and a pH regulator, and finally adding a monomer accounting for 10% of the total amount as an initial monomer; after the completion of the reaction, heating and boosting, adding an initiator into the reaction kettle; when the temperature is raised to 80 ℃ and the pressure is raised to 5.0-6.0MPa, the residual monomers are fed;

and (3) closing the ethylene feeding switch after the continuous monomer is added, then adding the defoaming agent and the bactericide, and finally filtering and discharging.

Further, the preparation method comprises the following steps:

A. preparation of the raw materials

A1. Preparing an initiator solution: adding 2.88-3.27 parts of water and 0.06-0.32 part of initiator into an initiator tank, stirring and dissolving to prepare an initiator solution with the mass fraction of 1.8% -10%;

A2. preparing a polyvinyl alcohol solution: adding 12.6-20.7 parts of water into a dissolving tank, starting stirring, adding 1.4-2.3 parts of polyvinyl alcohol, heating to 80 ℃ until the polyvinyl alcohol is completely dissolved, and preparing a polyvinyl alcohol solution with the mass fraction of 10%;

A3. preparing mixed monomers: adding 44.0-52.0 parts of vinyl acetate, 5.2-5.7 parts of carboxylic acid monomer and 1.5-3.5 parts of alcohol compound into a monomer tank, and stirring and mixing uniformly;

B. feeding production

Replacing the reaction kettle for 3 times by using nitrogen, adding water and the polyvinyl alcohol solution obtained in the step A2 into the reaction kettle, starting a stirrer, sequentially adding an emulsifier, a reducing agent and a pH regulator, and finally adding a mixed monomer accounting for 10% of the total amount as an initial monomer;

after the reaction is finished, the temperature of the reaction materials begins to rise, simultaneously, the pressure of the reaction kettle system is increased by ethylene, and when the pressure reaches 3.0-4.0MPa and the temperature rises to 52-76 ℃, the initiator is added into the reaction kettle at the speed of 0.6-2.4 g/min;

when the temperature of the reaction materials rises to 80 ℃, the ethylene pressure rises to 5.0-6.0MPa, and the residual mixed monomer starts to feed at the speed of 5.0-6.0 g/min;

during the continuous feeding of the mixed monomer, the ethylene pressure is maintained at 5.0-6.0MPa, and the reaction temperature is controlled at 80 +/-2 ℃;

after the continuous monomer is added, closing an ethylene feeding switch, and maintaining the reaction temperature at 80 +/-2 ℃;

when the ethylene pressure is lower than 1.3MPa, the reaction is finished;

reducing the temperature of the reaction materials to below 35 ℃, and adding 0.1-0.15% of defoaming agent and 0.1-0.2% of bactericide; and finally, filtering and discharging.

The invention has the beneficial effects that:

the adhesive strength of the vinyl acetate-ethylene copolymer emulsion is obviously improved, the composite peel strength of the terylene cloth and the non-woven fabric is 0.338-0.387N/mm, the adhesion between matrixes is firm, and the adhesive can be used for the adhesion in the occasions of textile, packaging, wood processing and the like.

The vinyl acetate-ethylene copolymer emulsion has good storage stability, and the viscosity change is 4.59-11.48% after the emulsion is placed indoors for 6 months at room temperature.

The method has simple production process and is suitable for industrial production.

The vinyl acetate-ethylene copolymer emulsion disclosed by the invention has excellent adhesive property and can meet the use requirements in the fields of wood processing, spinning, packaging, carpets and the like.

Detailed Description

The examples are provided for better illustration of the present invention, but the present invention is not limited to the examples. Therefore, those skilled in the art should make insubstantial modifications and adaptations to the embodiments of the present invention in light of the above teachings and remain within the scope of the invention.

Detecting the solid content, the ethylene content, the average particle size, the dilution stability and the filter residue content according to a test method of corresponding indexes in a vinyl acetate-ethylene copolymer emulsion national standard GB/T27573-2011 vinyl acetate-ethylene copolymer emulsion;

detecting the lower viscosity according to a viscosity testing method in the national standard GB/T27573-2011 vinyl acetate-ethylene copolymer emulsion of vinyl acetate-ethylene copolymer emulsion, wherein the testing temperature is 25 +/-0.1 ℃, and the instrument model is shown; brookfield LVDV-II +, rotor type No. 4 spindle, 60 rpm.

The following composite peel strength of polyester fabric and non-woven fabric was tested according to the test method for peel strength of adhesive T1995 GB/T2791 for flexible materials. Selecting Dacron cloth and non-woven fabric with thickness less than 3mm, and cutting the Dacron cloth and non-woven fabric into test pieces with length of 200mm and width of 25 + -0.5 mm. Uniformly coating the whole width of the terylene cloth test piece with the coating length of 150mm and the coating amount of 12g/m²After the completion, the nonwoven fabric test piece is aligned with the test piece, and is pressed by a test compounding machine with the roller temperature of 160 ℃ and the pressure of 1.0 MPa. The compounded sample is placed in an environment with the temperature of 23 ℃ and the humidity of 65% for 2 hours and then is tested by a microcomputer controlled universal testing machine, the testing machine is C43 of American MTS company, the testing environment temperature is 23 ℃ and the humidity is 65%, a 100N sensor is used for a testing instrument, the width of the sample is 25mm, and the thickness of the sample is 4 mm. When in test, the terylene and the non-woven fabric test piece are respectively clamped in an upper clamp and a lower clamp, a tensile machine is started to carry out the peeling force test at the displacement speed of 50mm/min, and when the sample is completely peeled (the adhesive coating is damaged), the average peeling strength displayed by a microcomputer is read as the test data of the sample. And (5) repeatedly performing test samples on each glue sample, and taking an average value as final test data.

Example 1

The vinyl acetate-ethylene copolymer emulsion is prepared by the following steps:

A. preparation of the raw materials

A1. Preparing an initiator solution: adding 38g of deionized water and 2.7g of 27.5 mass percent hydrogen peroxide solution into an initiator tank, and uniformly stirring and mixing to prepare 1.8 mass percent initiator solution;

A2. preparing a polyvinyl alcohol solution: adding 207g of deionized water into a dissolving tank, starting stirring, adding 23g of polyvinyl alcohol 1788, and heating to 80 ℃ until the polyvinyl alcohol is completely dissolved;

A3. preparing mixed monomers: adding 463g of vinyl acetate, 63g of acrylic acid and 21g of glycerol into a monomer tank, and uniformly stirring and mixing;

B. feeding production

Replacing the reaction kettle with nitrogen for three times, adding 253g of deionized water and 230g of the polyvinyl alcohol solution obtained in the step A into the reaction kettle, starting a stirrer, sequentially adding 3g of emulsifier OP-10, 1.3g of sodium erythorbate and 0.5g of sodium bicarbonate, and finally adding 52g of mixed monomer as an initial monomer;

after the reaction is finished, heating the reaction kettle by using a jacket, simultaneously boosting the pressure of the reaction kettle by using ethylene, and adding an initiator into the reaction kettle at a speed of 0.6g/min after the pressure reaches 3.5MPa and the temperature of reaction materials rises to 60 ℃;

when the reaction temperature was raised to 80 ℃, the ethylene pressure was raised to 5.5MPa, and the remainder of the mixed monomer was fed at a rate of 5.0 g/min;

during the continuous feeding of the mixed monomer, the ethylene pressure is maintained at 5.5MPa, and the reaction temperature is maintained at 80 +/-2 ℃ under the control of the feeding speed of the initiator by a computer;

after the continuous monomer feeding is finished, closing the ethylene feeding, and continuously controlling the feeding speed of the initiator by a computer to maintain the reaction temperature at 80 +/-2 ℃, and when the ethylene pressure is lower than 1.3MPa, finishing the reaction;

reducing the temperature of the reaction materials to below 35 ℃, and adding 1.8g of defoaming agent and 2.4g of bactericide; and finally, filtering and discharging.

The solid content, ethylene content, average particle size, dilution stability, residue content, and viscosity of the emulsion obtained in this example were measured, and a complex peel strength test of a polyester fabric and a nonwoven fabric was performed, and the emulsion was left indoors at room temperature (25 ± 0.5 ℃) for 6 months, and then the viscosity of the emulsion was measured again, and the results are shown in table 1.

TABLE 1 Properties of the emulsion prepared in example 1

Item	Index of emulsion
		Solids content%	55.3
Content of ethylene%	16.6
		viscosity/mPa.s	2658
Viscosity (after 6 months)/mPa.s	2780
		Average particle diameter, μm	0.897
Dilution stability,% of	1.8
		Content of residue in ppm	32
Terylene fabric and non-woven fabric composite peel strength/(N/mm)	0.387

Example 2

A. preparation of the raw materials

A1. Preparing an initiator solution: adding 34.2g of deionized water and 3.8g of ammonium persulfate into an initiator tank, stirring and dissolving to prepare 10% of initiator solution;

A2. preparing a polyvinyl alcohol solution: adding 216g of deionized water into a dissolving tank, starting stirring, adding 12g of polyvinyl alcohol 1788 and 12g of polyvinyl alcohol 1799, and heating to 85 ℃ until the polyvinyl alcohol is completely dissolved;

A3. preparing mixed monomers: adding 463g of vinyl acetate, 32g of acrylic acid and 18g of pentaerythritol into a monomer tank, and uniformly stirring and mixing;

B. feeding production

Replacing the reaction kettle with nitrogen for three times, adding 273g of deionized water and 240g of the polyvinyl alcohol solution obtained in the step A2 into the reaction kettle, starting a stirrer, sequentially adding 0.2g of sodium rongalite, 1.2g of disodium hydrogen phosphate and 3.6g of emulsifier OP-10, and finally adding 33g of mixed monomer as an initial monomer;

after the reaction is finished, heating by using a jacket, simultaneously boosting the pressure of the reaction kettle by using ethylene, adding an initiator into the reaction kettle at the speed of 2.4g/min when the pressure reaches 3.8MPa and the temperature of reaction materials rises to 76 ℃, and stopping initiator feeding after 5 min;

when the reaction temperature begins to rise and reaches 80 ℃, the ethylene pressure is increased to 5.0MPa, and the mixed monomer begins to be fed at the speed of 5.0 g/min;

during the continuous feeding of the mixed monomer, the ethylene pressure is maintained at 5.0MPa, the feeding speed of the initiator is maintained at 0.15g/min, and the reaction temperature is maintained at 80 +/-2 ℃ depending on the jacket temperature of the reaction kettle;

after the continuous monomer feeding is finished, closing an ethylene feeding switch, increasing the feeding speed of the initiator to 0.26g/min, continuously maintaining the reaction temperature at 80 +/-2 ℃ by depending on the water temperature of a jacket of the reaction kettle, and finishing the reaction when the ethylene pressure is lower than 1.3 MPa;

The emulsion obtained in this example was tested for solid content, ethylene content, average particle size, dilution stability, residue content, and viscosity, and further tested for peel strength between a polyester fabric and a nonwoven fabric, and the emulsion was allowed to stand indoors at room temperature (25 ± 0.5 ℃) for 6 months, and then the viscosity of the emulsion was again tested, and the results are shown in fig. 2.

Table 2 properties of the emulsion prepared in example 2

Item	Index of emulsion
		Solids content%	56.1
Content of ethylene%	15.3
		viscosity/mPa.s	3267
Viscosity (after 6 months)/mPa.s	3642
		Average particle diameter, μm	0.765
Dilution stability,% of	2.3
		Content of residue in ppm	40
Terylene fabric and non-woven fabric composite peel strength/(N/mm)	0.373

Example 3

A. preparation of the raw materials

A1. Preparing an initiator solution: adding 40g of deionized water and 4.4g of a hydrogen peroxide solution with the mass fraction of 30% into an initiator tank, stirring and mixing uniformly to prepare an initiator solution with the mass fraction of 3.0%;

A2. preparing a polyvinyl alcohol solution: adding 225g of deionized water into a dissolving tank, starting stirring, adding 16.67g of polyvinyl alcohol 1788 and 8.33g of polyvinyl alcohol 0588, and heating to 80 ℃ until the polyvinyl alcohol is completely dissolved;

A3. preparing mixed monomers: adding 463g of vinyl acetate, 55g of acrylic acid and 28g of glycerol into a monomer tank, and uniformly stirring and mixing;

B. feeding production

After the reaction kettle is replaced by nitrogen for three times, 235g of deionized water and 250g of polyvinyl alcohol solution are added into the reaction kettle, then 3.1g of emulsifier OP-10 is sequentially added, a stirrer is started, then 1.4g of sodium erythorbate and 0.5g of sodium bicarbonate are added, and finally 52g of mixed monomer is added to serve as initial monomer;

after the reaction is finished, heating the reaction kettle by using a jacket, simultaneously boosting the pressure of the reaction kettle by using ethylene, and adding an initiator into the reaction kettle at a speed of 0.5g/min after the pressure reaches 3.5MPa and the temperature of reaction materials rises to 60 ℃;

when the reaction temperature rose to 80 ℃, the ethylene pressure rose to 5.5MPa and the monomer mixture started to be fed at a rate of 6.0 g/min. During the continuous feeding of the mixed monomer, the ethylene pressure is maintained at 5.5MPa, and the reaction temperature is maintained at 80 +/-2 ℃ by controlling the feeding speed change of an initiator by a computer;

after the continuous monomer feeding is finished, closing an ethylene feeding switch, and continuously controlling the feeding speed of the initiator by a computer to maintain the reaction temperature at 80 +/-2 ℃, wherein when the ethylene pressure is lower than 1.3MPa, the reaction is finished;

The emulsion obtained in this example was tested for solid content, ethylene content, average particle size, dilution stability, residue content, and viscosity, and further tested for peel strength between a polyester fabric and a nonwoven fabric, and the emulsion was allowed to stand indoors at room temperature (25 ± 0.5 ℃) for 6 months, and then the viscosity of the emulsion was again tested, and the results are shown in fig. 3.

Table 3 properties of the emulsion prepared in example 3

Example 4

A. preparation of the raw materials

A2. preparing mixed monomers: adding 463g of vinyl acetate, 61g of acrylic acid and 23g of glycerol into a monomer tank, and uniformly stirring and mixing;

B. feeding production

After the reaction kettle is replaced by nitrogen for three times, 459g of deionized water is added into the reaction kettle, a stirrer is started, then 25.0g X-305 (octylphenol polyoxyethylene ether with the ethoxy number of 30), 6.0g X-100 (octylphenol polyoxyethylene ether with the ethoxy number of 10), 1.6g of sodium erythorbate and 0.5g of sodium bicarbonate are added, and finally 52g of mixed monomer is added as initial monomer;

after the reaction is finished, heating by using a jacket, simultaneously boosting the pressure of the reaction kettle by using ethylene, and adding an initiator into the reaction kettle at a speed of 0.6g/min after the pressure reaches 3.4MPa and the temperature of reaction materials rises to 60 ℃;

The emulsion obtained in this example was tested for solid content, ethylene content, average particle size, dilution stability, residue content, and viscosity, and further tested for peel strength between a polyester fabric and a nonwoven fabric, and the emulsion was allowed to stand indoors at room temperature (25 ± 0.5 ℃) for 6 months, and then the viscosity of the emulsion was again tested, and the results are shown in fig. 4.

Table 4 properties of the emulsion prepared in example 4

Example 5

A. preparation of the raw materials

A2. preparing a polyvinyl alcohol solution: adding 225g of deionized water into a dissolving tank, starting stirring, adding 19.67g of polyvinyl alcohol 1788 and 5.33g of polyvinyl alcohol 1088, and heating to 80 ℃ until the polyvinyl alcohol is completely dissolved;

A3. preparing mixed monomers: adding 463g of vinyl acetate, 52g of acrylic acid and 31g of ethylene glycol into a monomer tank, and uniformly stirring and mixing;

B. feeding production

After the reaction kettle is replaced by nitrogen for three times, 235g of deionized water and 250g of polyvinyl alcohol solution are added into the reaction kettle, then a stirrer is started, 1.3g of sodium erythorbate and 0.6g of sodium bicarbonate are added, and finally 54g of mixed monomer is added to serve as initial monomer;

after the reaction is finished, heating the reaction kettle by using a jacket, simultaneously boosting the pressure of the reaction kettle by using ethylene, and adding an initiator into the reaction kettle at a speed of 0.5g/min after the pressure reaches 3.7MPa and the temperature of reaction materials rises to 60 ℃;

when the reaction temperature rose to 80 ℃, the ethylene pressure rose to 5.8MPa and the monomer mixture started to be fed at 6.0 g/min. During the continuous feeding of the mixed monomer, the ethylene pressure is maintained at 5.8MPa, and the reaction temperature is maintained at 80 +/-2 ℃ by controlling the feeding speed change of an initiator by a computer;

The emulsion obtained in this example was tested for solid content, ethylene content, average particle size, dilution stability, residue content, and viscosity, and further tested for peel strength between a polyester fabric and a nonwoven fabric, and the emulsion was allowed to stand indoors at room temperature (25 ± 0.5 ℃) for 6 months, and then the viscosity of the emulsion was again tested, and the results are shown in fig. 5.

TABLE 5 Properties of the emulsions prepared in example 5

As is apparent from tables 1 to 5, the vinyl acetate-ethylene copolymer emulsions prepared in examples 1 to 5 exhibited a viscosity change of 4.59 to 11.48% and a complex peel strength of the terylene fabric and the nonwoven fabric of 0.338 to 0.387N/mm when left standing at room temperature for 6 months. Therefore, the adhesive strength of the vinyl acetate-ethylene copolymer emulsion is obviously improved, and the vinyl acetate-ethylene copolymer emulsion has good storage stability.

Furthermore, it should be understood that although the present description refers to embodiments, not every embodiment may contain only a single embodiment, and such description is for clarity only, and those skilled in the art should integrate the description, and the embodiments may be combined as appropriate to form other embodiments understood by those skilled in the art.

Claims

1. The vinyl acetate-ethylene copolymer emulsion is characterized by being prepared from raw materials including a monomer, an emulsifying system, an initiator, a reducing agent, a pH regulator and water, wherein the monomer comprises alcohols with the carbon atom number of 2-8 and the number of alcoholic hydroxyl groups of more than or equal to 2.

2. The vinyl acetate-ethylene copolymer emulsion according to claim 1, wherein the alcohol is 1 to 3 of ethylene glycol, glycerin and pentaerythritol.

3. The vinyl acetate-ethylene copolymer emulsion according to claim 2, wherein the alcohol is ethylene glycol or glycerin.

4. The vinyl acetate-ethylene copolymer emulsion of any one of claims 1 to 3 wherein the monomer comprises a carboxylic acid monomer.

5. The vinyl acetate-ethylene copolymer emulsion according to claim 4, wherein the carboxylic acid monomer is acrylic acid or an acrylic acid derivative or a combination thereof.

6. The vinyl acetate-ethylene copolymer emulsion according to claim 5, wherein the acrylic acid derivative is methacrylic acid.

7. The vinyl acetate-ethylene copolymer emulsion according to any of claims 2 to 6, wherein the monomers further comprise vinyl acetate and ethylene.

8. The vinyl acetate-ethylene copolymer emulsion according to claim 7, wherein the monomers comprise, by mass, 44.0 to 52.0 parts of vinyl acetate, a proper amount of ethylene, 5.2 to 5.7 parts of carboxylic acid monomer, and 1.5 to 3.5 parts of alcohol.

9. The vinyl acetate-ethylene copolymer emulsion according to any one of claims 1 to 8, wherein the emulsifying system is a protective colloid or an emulsifier or a combination thereof.

10. The vinyl acetate-ethylene copolymer emulsion as claimed in claim 9, wherein the protective colloid is one or more of polyvinyl alcohol with a degree of polymerization of 500-2400 and a degree of alcoholysis of 88-99%.

11. The vinyl acetate-ethylene copolymer emulsion according to claim 9 or 10, wherein the emulsifier is octylphenol polyoxyethylene ether having 10 or 30 ethoxy groups or a combination thereof.

12. The vinyl acetate-ethylene copolymer emulsion according to any one of claims 1 to 11, wherein the initiator is a peroxide initiator.

13. The emulsion of claim 12, wherein the peroxide initiator is 1 to 4 of hydrogen peroxide, potassium persulfate, ammonium persulfate, and t-butyl hydroperoxide.

14. The vinyl acetate-ethylene copolymer emulsion according to any one of claims 1 to 13, wherein the reducing agent is 1 to 6 of ascorbic acid, sodium erythorbate, tartaric acid, sodium sulfite, sodium rongalite and sodium metabisulfite.

15. The vinyl acetate-ethylene copolymer emulsion according to any one of claims 2 to 15, wherein the PH adjuster is 1 to 4 of sodium acetate, sodium bicarbonate, sodium carbonate and disodium hydrogen phosphate.

16. The vinyl acetate-ethylene copolymer emulsion according to any one of claims 1 to 15, wherein the compounding ratio is, in parts by mass: 49.2-57.7 parts of vinyl acetate, a proper amount of ethylene, 5.2-5.7 parts of carboxylic acid monomer, 2.4-3.0 parts of an emulsifying system, 0.06-0.32 part of an initiator, 0.017-0.13 part of a reducing agent, 1.5-3.5 parts of alcohols, 0.04-0.13 part of a pH regulator and 40.0-45.0 parts of water.

17. The method for preparing vinyl acetate-ethylene copolymer emulsion according to any one of claims 1 to 16, wherein the vinyl acetate-ethylene copolymer emulsion is prepared by a semi-continuous emulsion polymerization method.

18. The method of claim 17, comprising the steps of: raw material preparation and feeding production, wherein the feeding production process specifically comprises the following steps:

19. The method of claim 18, comprising the steps of:

A. preparation of the raw materials

A3. preparing mixed monomers: adding 44.0-52.0 parts of vinyl acetate, 5.2-5.7 parts of carboxylic acid monomer and 1.5-3.5 parts of alcohol into a monomer tank, and stirring and mixing uniformly;

B. feeding production

when the ethylene pressure is lower than 1.3MPa, the reaction is finished;