Odorless pure acrylic emulsion for bi-component plate alignment adhesive and preparation method thereofTechnical Field
The invention belongs to the technical field of emulsion polymerization, and particularly relates to an odorless acrylic emulsion for bi-component plate alignment adhesive and a preparation method thereof.
Background
The bi-component plate alignment adhesive is used as an adhesive for wooden products such as plate-aligned laminated wood and the like, and belongs to a quick adhesion type. The method is widely applied to splicing production of structural or non-structural laminated wood in the fields of artificial boards, jointed boards, composite floors and the like. The main agent of the bi-component plate alignment adhesive is polyvinyl acetate emulsion which is specially made and has no excellent air permeability, and the curing agent is isocyanate. The primary make-up glue can be used alone to refer to the glue. The two-component plate alignment adhesive is a water-based high-molecular isocyanate adhesive (called EPI adhesive), which is a two-component adhesive containing water-based polymers containing active hydrogen and isocyanate as a bridging agent.
Along with the improvement of living standard of people, the market of solid wood splicing laminated wood is larger and larger, and the market of plate splicing glue is rapidly expanded. However, most of the high-end laminated materials are produced by using imported or joint-venture brands of plate alignment adhesives, such as Guangyang, Aike, Xiaoxi, Han and the like, but the price is expensive. The low-grade plate alignment adhesive in China is vinyl acetate-acrylic emulsion or VAE emulsion and partial large 905 emulsion, and the problems of short service life, poor water resistance, unsatisfactory heat resistance, low-temperature hardness and brittleness of the adhesive film mainly exist. The styrene-acrylic emulsion with 905 at a higher end improves the water resistance, but the styrene-acrylic emulsion can have unpleasant bitter almond smell, and with the further advancement of environmental requirements, the requirements of customers on low smell and even smell become higher and higher, so that the development of the pure acrylic emulsion with smell purification for the bi-component plate splicing adhesive can well meet the requirements of market development, and has good development prospect.
Disclosure of Invention
The invention provides an odorless acrylic emulsion for bi-component plate alignment adhesive and a preparation method thereof, aiming at improving the defects of the emulsion for bi-component plate alignment adhesive at present.
The invention adopts the following technical scheme that the odorless pure acrylic emulsion for the bi-component plate alignment adhesive comprises the following components in parts by weight: 10-25 parts of butyl acrylate, 15-30 parts of methyl methacrylate, 0.1-1 part of acrylic acid, 1-3 parts of hydroxyl monomer, 0.5-2 parts of functional monomer, 0.5-2 parts of A171 silane coupling agent, 0.2-2.5 parts of initiator, 0.5-2 parts of emulsifier, 40-50 parts of deionized water, 2 parts of baking soda, 0.15-1 part of oxidant, 0.15-1 part of reducing agent and 0.1 part of defoaming agent.
Further, the emulsifier is formed by mixing a negative nonionic emulsifier and a reactive emulsifier according to the weight ratio of 1: 1-1: 4.
Further, the anionic and nonionic emulsifier is formed by mixing one or more of the following components of sand rope 3400, Dow CA-90, Dow EH-9 and Solvay A102 according to any proportion; the reactive emulsifier is prepared by mixing one or more of Idiaceae SE-10N, Idiaceae ER-10, Solvay SVS-25 and Solvay COPS-1 according to any proportion.
Further, the hydroxyl monomer is formed by mixing one or more of hydroxyethyl methacrylate, hydroxypropyl methacrylate and hydroxybutyl acrylate according to any proportion.
Further, the functional monomer is a mixture of DAAM and ADH in a weight ratio of 1:1, hydroxyethyl modified acrylamide, hydroxyethyl modified ureide or acetoxyethyl methacrylate.
Further, the initiator is a potassium persulfate aqueous solution with the concentration of 20 wt% to 50 wt%.
Further, the oxidant is a tert-butyl hydrogen peroxide aqueous solution with the concentration of 5 wt% to 10 wt%, and the reducing agent is an ascorbic acid aqueous solution with the concentration of 5 wt% to 10 wt%.
Further, the antifoaming agent is adico B-548.
The preparation method of the pure acrylic emulsion is characterized by comprising the following steps:
(1) material taking: 10-25 parts of butyl acrylate, 15-30 parts of methyl methacrylate, 0.1-1 part of acrylic acid, 1-3 parts of hydroxyl monomer, 0.5-2 parts of functional monomer, 0.5-2 parts of A171 silane coupling agent, 0.2-2.5 parts of initiator, 0.5-2 parts of emulsifier, 40-50 parts of deionized water, 2 parts of baking soda, 0.075-0.1 part of oxidant, 0.075-0.1 part of reducing agent and 0.1 part of defoaming agent.
(2) Pre-emulsification: adding an emulsifier into 15-25 parts by weight of deionized water, sequentially adding butyl acrylate, methyl methacrylate, acrylic acid, a hydroxyl monomer, a functional monomer and an A171 silane coupling agent, and uniformly mixing to obtain a pre-emulsion.
(3) Emulsion polymerization: adding baking soda and the rest deionized water into a reaction kettle, uniformly stirring, heating to 78-82 ℃, adding 0.08-1 part by weight of initiator, and simultaneously dropwise adding the pre-emulsion obtained in the step (2) and the rest initiator for 4-5 hours at the temperature of 80-85 ℃; after the dropwise addition, heating to 85-90 ℃, and keeping the temperature for more than 1h to obtain the emulsion.
(4) And (3) post-treatment: cooling the emulsion obtained in the step (3) to 65-72 ℃, simultaneously dropwise adding an oxidant and a reducing agent, controlling the dropwise adding time to be 20-30 min, and preserving heat for 30min after dropwise adding; cooling to 50 ℃, adding a defoaming agent, and filtering to obtain the odorless pure acrylic emulsion.
The invention has the beneficial effects that: when the emulsifier in the formula is used, the anionic non-ionic emulsifier and the reactive emulsifier are mixed according to the weight ratio of 1: 1-1: 4, and molecules of the reactive emulsifier are combined through covalent bonds, so that the emulsion cannot be absorbed and decomposed in the storage and use processes, the storage stability is good, the migration of the emulsifier is avoided, and the mechanical property, the cohesiveness, the water resistance and the like of the adhesive film are greatly improved. When the use amount of the anionic nonionic emulsifier is too large, the water resistance of the emulsion is reduced, so that the reduction of the wet strength of the emulsion in the compounding and using process is reduced; when the dosage is too small, the emulsion polymerization stability is poor, so the emulsion is prepared by mixing the components in a weight ratio of 1: 1-1: 4.
0.5-2 parts by weight of silane coupling agent is introduced into the formula, and because the polysiloxane molecular main chain structure has high Si-0 bond energy, large molecular volume and low cohesive energy density, the polysiloxane molecular main chain structure has good high and low temperature resistance, hydrophobicity, air permeability and weather resistance. The organic silicon resin has high molecular symmetry, and the whole molecule is nonpolar, so that the organic silicon resin has very low surface tension, and a coating film has good water repellency. A-171 also contains 3 reactive methoxyl groups, and cross-linking points can be formed through the hydrolytic condensation reaction of the methoxyl groups to obtain the pure acrylic emulsion with a core cross-linking structure. Because the si-0 bond energy (454kJ/mol) in the resin is far more than the c-0 bond energy (345kJ/mol) and the c-c bond energy (351kJ/mol), the modified pure acrylic emulsion prepared by introducing the si-0 bond energy into the acrylate chain segment has the characteristic of strong hydrophobicity. The silane coupling agent has the characteristic of easy hydrolysis, when the addition amount exceeds the proportion amount, the emulsion is easy to have poor stability, and the synthetic emulsion is reduced along with the increase of the addition amount of the silane coupling agent in the detection of water resistance and wet strength.
10-25 parts by weight of butyl acrylate and 15-30 parts by weight of methyl methacrylate are selected, so that the emulsion has flexibility and strength in performance.
The odor-free emulsion prepared by adopting a polymerization process and a monomer ratio has the characteristics of zero formaldehyde, low VOC and low odor, meets the national ten-ring environmental protection standard, and has dry and wet strength which passes the Japanese agriculture and forestry specification JISK6806-2003 standard test on the compound plate adhesive.
Detailed Description
In order to make the purpose and technical solutions of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly described below, and it is obvious that the described embodiments are a part of the embodiments of the present invention, but not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
Example 1
(1) Material taking: 150g of butyl acrylate, 260g of methyl methacrylate, 1g of acrylic acid, 25g of hydroxyethyl methacrylate, 10g of hydroxyethyl-modified acrylamide, 20g A171 g of a silane coupling agent, 2g of a 20 wt% aqueous potassium persulfate solution, 8g of emulsifiers (1 g of a saso 3400 emulsifier, 2g of a Dow CA-90 emulsifier and 5g of an Adeca SE-10N emulsifier), 400g of deionized water, 0.2g of baking soda, 1.5g of a 5 wt% aqueous tert-butyl hydroperoxide solution, 1.5g of a 5 wt% aqueous ascorbic acid solution, 1g of Adeca B-548.
(2) Pre-emulsification: 1g of a halyard 3400 emulsifier, 2g of a Dow CA-90 emulsifier and 5g of an Edaceae SE-10N emulsifier are added into 150g of deionized water to be uniformly dispersed, then 150g of butyl acrylate, 260g of methyl methacrylate, 1g of acrylic acid, 25g of hydroxyethyl methacrylate, 10g of hydroxyethyl modified acrylamide and 20g A171 silane coupling agent are sequentially added, and after uniform mixing, a pre-emulsion is obtained for later use.
(3) Emulsion polymerization: uniformly stirring 250g of deionized water and 0.2g of baking soda, heating to 82 ℃, adding 0.8g of potassium persulfate aqueous solution, and simultaneously dropwise adding the pre-emulsion and the residual potassium persulfate aqueous solution for 4.5h, wherein the dropwise adding temperature is controlled at 82 ℃; after the dropwise addition, the temperature is raised to 85 ℃, and the temperature is kept for 1h to obtain the emulsion.
(4) And (3) post-treatment: cooling the emulsion obtained in the step 3 to 65 ℃, simultaneously dropwise adding 1.5g of 5 wt% tert-butyl hydroperoxide aqueous solution and 1.5g of 5 wt% ascorbic acid aqueous solution for 20min, and preserving heat for 30min after dropwise adding; cooling to 50 deg.C, 1g of Aidicke B-548, and filtering to obtain pure acrylic emulsion.
The physical property indexes of the odorless acrylic emulsion prepared in example 1 were measured according to GB/T11175-2002, GB1852-2008 and GB1853-2008, and the results of the measurements of the average particle size of the emulsion by an MS-2000 laser particle size analyzer are shown in Table 1.
Example 2
(1) Material taking: 200g of butyl acrylate, 150g of methyl methacrylate, 5g of acrylic acid, 20g of hydroxypropyl methacrylate, 15g of hydroxyethyl-modified acryloylurea, 5g A171 g of a silane coupling agent, 25g of a 20 wt% aqueous potassium persulfate solution, 5g of emulsifiers (0.5 g of Dow EH-9 emulsifier, 0.5g of Solvay A-102 emulsifier and 4g of Idekco ER-10 emulsifier), 400g of deionized water, 0.2g of baking soda, 10g of a 5 wt% aqueous tert-butyl hydroperoxide solution, 10g of a 5 wt% aqueous ascorbic acid solution, and 1g of Idekco B-548.
(2) Pre-emulsification: 0.5g of Dow EH-9 emulsifier, 0.5g of Solvay A-102 emulsifier and 4g of Ethicco ER-10 emulsifier are added into 200g of deionized water to be dispersed uniformly, 200g of butyl acrylate, 150g of methyl methacrylate, 5g of acrylic acid, 20g of hydroxypropyl methacrylate, 15g of hydroxyethyl modified acrylurea and 5g A171 silane coupling agent are sequentially added to be mixed uniformly, and pre-emulsion is obtained for later use.
(3) Emulsion polymerization: uniformly stirring 200g of deionized water and 0.2g of baking soda, heating to 82 ℃, adding 10g of potassium persulfate aqueous solution, and simultaneously dropwise adding the pre-emulsion and the residual potassium persulfate aqueous solution for 4.5 hours at the temperature of 82 ℃; after the dropwise addition, the temperature is raised to 85 ℃, and the temperature is kept for 1h to obtain the emulsion.
(4) And (3) post-treatment: cooling the emulsion obtained in the step (3) to 65 ℃, simultaneously dropwise adding 10g of 5 wt% tert-butyl hydrogen peroxide aqueous solution and 10g of 5 wt% ascorbic acid aqueous solution for 20min, and preserving heat for 30min after dropwise adding; cooling to 50 deg.C, 1g of Aidicke B-548, and filtering to obtain pure acrylic emulsion.
The physical property indexes of the odorless acrylic emulsion prepared in example 2 were measured according to GB/T11175-2002, GB1852-2008 and GB1853-2008, and the results of the measurements of the average particle size of the emulsion by an MS-2000 laser particle size analyzer are shown in Table 1.
Example 3
(1) Material taking: 100g of butyl acrylate, 300g of methyl methacrylate, 8g of acrylic acid, 30g of hydroxybutyl methacrylate, 5g of acetoxyethyl methacrylate, 10g A171 g of a silane coupling agent, 10g of a 50 wt% aqueous potassium persulfate solution, 7g of emulsifiers (sasuo 3400 emulsifier 2g, solva A-102 emulsifier 1g and solva SVS-25 emulsifier 4g), 500g of deionized water, 0.2g of baking soda, 5g of a10 wt% aqueous solution of tert-butyl hydroperoxide, 5g of a10 wt% aqueous solution of ascorbic acid, 1g of Aidicke B-548.
(2) Pre-emulsification: 2g of a saxole 3400 emulsifier, 1g of a solva A-102 emulsifier and 4g of a solva SVS-25 emulsifier are added into 250g of deionized water to be uniformly dispersed, then 100g of butyl acrylate, 300g of methyl methacrylate, 8g of acrylic acid, 30g of hydroxybutyl methacrylate, 5g of acetoxyethyl methacrylate and 10g A171 silane coupling agent are sequentially added, and after uniform mixing, a pre-emulsion is obtained for later use.
(3) Emulsion polymerization: uniformly stirring 250g of deionized water and 0.2g of baking soda, heating to 82 ℃, adding 4g of potassium persulfate aqueous solution, and simultaneously dropwise adding the pre-emulsion and the residual potassium persulfate aqueous solution for 4 hours at the temperature of 85 ℃; after the dropwise addition, the temperature is raised to 85 ℃, and the temperature is kept for 1h to obtain the emulsion.
(4) And (3) post-treatment: cooling the emulsion obtained in the step (3) to 72 ℃, simultaneously dropwise adding 5g of 10 wt% tert-butyl hydrogen peroxide aqueous solution and 5g of 10 wt% ascorbic acid aqueous solution for 30min, and preserving heat for 30min after dropwise adding; cooling to 50 deg.C, 1g of Aidicke B-548, and filtering to obtain pure acrylic emulsion.
The physical property indexes of the odorless acrylic emulsion prepared in example 3 were measured according to GB/T11175-2002, GB1852-2008 and GB1853-2008, and the results of the measurements of the average particle size of the emulsion by an MS-2000 laser particle size analyzer are shown in Table 1.
Example 4
(1) Material taking: 250g of butyl acrylate, 260g of methyl methacrylate, 10g of acrylic acid, 10g of hydroxybutyl acrylate, 10g of DAAM, 10g of AHD, 8g A171 of a silane coupling agent, 10g of a 50 wt% aqueous solution of potassium persulfate, 20g of emulsifiers (6 g of Dow EH-9 emulsifier, 4g of Dow CA-90 emulsifier and 10g of Solvay C0PS-1 emulsifier), 500g of deionized water, 0.2g of baking soda, 5g of a10 wt% aqueous solution of tert-butyl hydroperoxide, 5g of a10 wt% aqueous solution of ascorbic acid, 1g of Idekisco B-548.
(2) Pre-emulsification: 6g of Dow EH-9 emulsifier, 4g of Dow CA-90 emulsifier and 10g of Solvay C0PS-1 emulsifier are added into 170g of deionized water to be uniformly dispersed, 250g of butyl acrylate, 260g of methyl methacrylate, 10g of acrylic acid, 10g of hydroxybutyl acrylate, 10g of DAAM and 8g A171 silane coupling agent are sequentially added into the mixture, and the mixture is uniformly mixed to obtain pre-emulsion for later use.
(3) Emulsion polymerization: uniformly stirring 330g of deionized water and 0.2g of baking soda, heating to 78 ℃, adding 4g of potassium persulfate aqueous solution, and simultaneously dropwise adding the pre-emulsion and the residual potassium persulfate aqueous solution for 5 hours at the temperature of 80 ℃; after the dropwise addition, the temperature is raised to 85 ℃, and the temperature is kept for 1h to obtain the emulsion.
(4) And (3) post-treatment: cooling the emulsion obtained in the step (3) to 65 ℃, simultaneously dropwise adding 5g of 10 wt% tert-butyl hydrogen peroxide aqueous solution and 5g of 10 wt% ascorbic acid aqueous solution for 20min, and preserving heat for 30min after dropwise adding; cooling to 50 deg.C, adding 10g AHD and 1g Adecaco B-548, and filtering to obtain pure acrylic emulsion.
The physical property indexes of the odorless acrylic emulsion prepared in example 4 were measured according to GB/T11175-2002, GB1852-2008 and GB1853-2008, and the results of the measurements of the average particle size of the emulsion by an MS-2000 laser particle size analyzer are shown in Table 1.
TABLE 1 physical Properties of neat acrylic emulsion
| Index (I) | Example 1 | Example 2 | Example 3 | Example 4 |
| Appearance of the product | Pure white emulsion | Pure white emulsion | Pure white emulsion | Pure white emulsion |
| pH value | 5.23 | 5.34 | 5.1 | 5.2 |
| Viscosity of the oil | 310mpa.s | 400mpa.s | 280mpa.s | 500mpa.s |
| Solid content | 49.5 | 50.1 | 49.8 | 50.4 |
| Voc | 50ppm | 80ppm | 60ppm | 70ppm |
| Free formaldehyde | Not detected out | Not detected out | Not detected out | Not detected out |
| Average particle diameter | 350nm | 430nm | 380nm | 370nm |
As can be seen from the test data in Table 1, the average particle size of the emulsion controlled by the odorless acrylic emulsion prepared by the invention is 300-500nm, the appearance of the emulsion is pure white emulsion, the appearance of the compounded plate alignment adhesive is not obviously affected, the emulsion synthesized by reasonable monomer proportion, polymerization process and post-treatment meets the national standard ten-ring standard in the detection of Voc and free formaldehyde, and the Voc meets the requirements of odorless and low odor.
The neat acrylic emulsions obtained in examples 1-4 were evaluated for the following tests: 100g of Sichuan polyvinyl alcohol BP-248815% aqueous solution is taken from four containers respectively, 16g of water and 0.5g of dispersing agent are added into the aqueous solution, the dispersing and stirring are carried out uniformly for 20min, 80g of 800-mesh calcium carbonate is added into the aqueous solution, the dispersing and stirring are carried out uniformly for 30min, 100g of the pure acrylic emulsion obtained in the four examples are added respectively, and the main agent for the bi-component plate alignment adhesive of the four different examples is obtained. When in performance detection, the weight ratio of the main agent to the curing agent is 100: 15. 50g of the compounded main agent of the plate alignment adhesive obtained in the corresponding examples 1-4 and 7.5g of the curing agent are uniformly mixed, and a 30X 25X 10mm standard beech test block is selected, and 36 groups of test pieces are prepared according to the standard method of the Japanese JIS K6806-2003, the pressure is 8atm, and the pressure is released after 24 hours of pressing. The results of the measurement of the press shear strength are shown in Table 2 (each data is an average value of 10 test pieces).
TABLE 2 Dry and Wet bond Strength Performance test
The test data in Table 2 show that the plate alignment adhesive prepared by compounding the odorless acrylic emulsion completely meets the requirements of the industrial standard JIS K6806-2003. The high dry strength is achieved through reasonable monomer proportion; the used reactive emulsifier and the anionic nonionic emulsifier are matched, the silane coupling agent is used, and the functional monomer is added, so that the emulsion has excellent water resistance and hydrophobic property, and excellent temperature water resistance and boiling water resistance in detection data are obtained.