CN1986582A - Emulsion polymerization process for in-situ preparing nano SiO2/acrylate resin composite paint - Google Patents

Abstract

The invention relates to a preparation method of a nano SiO ₂ /acrylic resin composite finishing agent generated in situ by emulsion polymerization, in particular to a preparation method of a soft acrylic resin leather finishing agent which can be used for leather bottom coating and middle coating. Acrylic resin is the most widely used film-forming substance in leather finishing, and its dosage accounts for more than 70% of the film-forming substance in leather finishing. The acrylic resin leather finishing agent has strong adhesion, and the coating film is smooth and bright. High resistance, stable structure and aging resistance, but there are also disadvantages such as "hot stickiness, cold brittleness", no solvent resistance, and poor weather resistance. The present invention uses orthosilicate and acrylate monomers as raw materials, adopts emulsion polymerization to synthesize acrylic resin/nanometer _SiO2 composite material in situ, and uses it for leather finishing, overcomes the shortcoming of traditional acrylic resin, Good aging resistance, especially suitable for garment leather finishing, after finishing the leather sample has a good feel, and its hygienic performance is obviously improved.

Description

Preparation method of in-situ nano-SiO2/acrylic resin composite coating agent generated by emulsion polymerization

Technical field:

The invention relates to a preparation method of a nano SiO ₂ /acrylic resin composite finishing agent generated in situ by emulsion polymerization, in particular to a preparation method of a soft acrylic resin leather finishing agent which can be used for leather bottom coating and middle coating.

technical background:

Acrylic resin is the most widely used film-forming substance in leather finishing, and its dosage accounts for more than 70% of the film-forming substance in leather finishing. Acrylic resin leather finishing agent has strong adhesion, smooth and bright coating film, flex resistance, extension It has strong resistance, stable structure and aging resistance, but it also has the disadvantages of "hot stickiness, cold brittleness", no solvent resistance, poor weather resistance, etc., so its application is limited.

In recent years, nanomaterials have attracted the attention of scientists all over the world due to their excellent performance, and are considered to be a frontier strategic field in the 21st century. The application of nanomaterials has been successful to a certain extent. Organic/inorganic nanocomposite materials have rapidly become one of the research hotspots in the field of nanotechnology because of their unique properties (Liang Hongbin. Research progress in polymer/nanocomposite materials [J]. Chemical Engineer, 2001(6): 26-28; Xu Guocai , Zhang Lide. Nanocomposites [M]. Beijing: Chemical Industry Press, 2002, 3.).

Nano-material modified acrylic resin has many successful examples as architectural coatings (Wu Limin. Research and development and industrialization of nano-coatings. New material industry [J]. 2002, (2): 60.), theoretically for This study laid the foundation for the possibility of nanomaterials composited with acrylic resin as a leather finishing agent, that is, the use of nanocomposites for leather finishing is feasible. The use of nano _-SiO2 in the modification of leather finishing agents will endow the coating with good solvent resistance, weather resistance, strength, and toughness, and at the same time improve the wearing comfort of the finished leather. In addition, due to the special optical properties of _SiO2 , the coating can be Shields ultraviolet rays and greatly improves the aging resistance of the coating. The small size effect of nano-SiO ₂ makes it produce stasis effect, which greatly improves the scrub resistance and surface self-cleaning property of the coating (YCChen, SXZhou, HHYang, etc..Structure and properties orpolyurethane/nano silica composites[J].Journal of Applied Polymer Science, 2005, 95: 1032-1039.), the successful research and widespread use of nanomaterial modified leather finishing agents can solve the thorny problems that have plagued tanners for many years.

Invention content:

The object of the present invention is to provide a kind of preparation method that adopts emulsion polymerization to generate nano- _SiO2 /acrylic resin composite finishing agent in situ, and the modified acrylic resin leather finishing agent prepared by it has improved the air permeability and water vapor permeability of leather, and makes leather It has good hygienic performance.

In order to achieve the above object, the technical scheme adopted in the present invention is:

A preparation method for in-situ generation of nano- _SiO2 /acrylic resin composite coating agent by emulsion polymerization,

The mole fraction composition scope of its raw material is:

Acrylic monomer 14-15%

Emulsifier 0.40-0.75%

Organosilane coupling agent 0.40-1.1%

Ethyl orthosilicate 0.07-0.3%

Initiator 0.07-0.23%

The rest is deionized water;

Its preparation method is:

Heat the three-necked flask in a water bath to 40-45°C, add emulsifier and deionized water, after the emulsification is uniform, add organosilane coupling agent and ethyl orthosilicate, after constant temperature reaction for 10 minutes, add acrylate monomer total mass 1/5 and 1/4 of the mass of the initiator aqueous solution, the temperature was raised to 80-83°C, and after 30 minutes of reaction, the remaining acrylate monomer and initiator were added dropwise, and after the addition was completed, the temperature was raised to 85-90°C. After stirring for 2 hours, lower the temperature and adjust the pH to neutral to obtain the nano-SiO ₂ /acrylic resin composite coating agent;

The above-mentioned emulsifier is composed of nonionic surfactant and anionic surfactant in a molar ratio of 2:1; the nonionic surfactant is alkylphenol polyoxyethylene ether, alkyl polyglycoside, sorbitan monooleic acid Any one in ester (Span80); Anionic surfactant is any one in sodium lauryl sulfate, sodium dodecylbenzenesulfonate;

The above-mentioned initiator is any one of potassium persulfate and ammonium persulfate.

The above-mentioned acrylate monomers are two or more of butyl acrylate, ethyl acrylate, methyl acrylate, methyl methacrylate, butyl methacrylate and vinyl acetate.

Compared with the prior art, the present invention has the following advantages:

In the present invention, the nano- _SiO2 /acrylic resin leather finishing agent is generated in situ by emulsion polymerization, which has good stability, and the porosity in the leather coating increases due to the existence of the -Si-O-Si- structure, and the internal activity The increase of the group greatly improves the air permeability and water vapor permeability of the leather, so that the leather has good hygienic performance. Due to the existence of nano-SiO ₂ , the nano-SiO ₂ /acrylic resin composite material has good optical properties, which can increase the transparency of the coating when used in leather finishing. At the same time, the enhanced toughening performance of nanoparticles can improve the strength of the leather coating. , To a certain extent, it makes up for the deficiency of conventional acrylic resin leather finishing agents.

Detailed ways:

Example 1: The three-necked flask was heated to 40°C in a water bath, and an emulsifier (the molar ratio of alkylphenol polyoxyethylene ether to sodium lauryl sulfate was 2:1) and deionized water with a molar fraction of 0.5% was added, and the After the emulsification is uniform, add a mole fraction of 0.4% organosilane coupling agent and a mole fraction of 0.07% tetraethyl orthosilicate, and stir at a constant temperature for 10 minutes, then add a mole fraction of 14% butyl acrylate and methyl methacrylate (acrylic acid The molar ratio of butyl ester and methyl methacrylate is 2: 1) 1/5 of the total mass of the mixed monomer and 1/4 of the mass of potassium persulfate aqueous solution with a mole fraction of 0.07%, the system is heated up to 80°C, and reacted for 30min Then start to drop the remaining monomer and initiator aqueous solution respectively. After the dropwise addition, raise the temperature to 88° C., stir for 2 hours, then lower the temperature to adjust the pH to neutral, and obtain the nano-SiO ₂ /acrylic resin composite coating agent.

Example 2: Heat the three-necked flask in a water bath to 45°C, add an emulsifier with a molar fraction of 0.5% (the molar ratio of alkyl polyglycosides to sodium lauryl sulfate is 2:1) and deionized water, and wait for the emulsification to be uniform Finally, adding mole fraction is 0.8% organic silane coupling agent and mole fraction 0.1% tetraethyl orthosilicate, after stirring at constant temperature for 10min, adding mole fraction is 14.5% ethyl acrylate and methyl acrylate (ethyl acrylate and The molar ratio of methyl acrylate is 2: 1) 1/5 of the total mass of the mixed monomers and 1/4 of the mass of the ammonium persulfate aqueous solution with a mole fraction of 0.1%, and the temperature is raised to 82°C, and the remaining monomers are added dropwise after 30 minutes of reaction. After the dropwise addition, raise the temperature to 86° C., stir for 2 hours, and lower the temperature to adjust the pH to neutral to obtain the nano-SiO ₂ /acrylic resin composite coating agent.

Example 3: The three-necked flask was heated to 42°C in a water bath, and the emulsifier (the molar ratio of sorbitan monooleate to sodium lauryl sulfate was 2:1) and deionized water was added with a molar fraction of 0.6% , after the emulsification is uniform, adding mole fraction is 0.6% organosilane coupling agent and mole fraction 0.2% orthosilicate ethyl ester, after stirring at constant temperature for 10min, adding mole fraction is 15% butyl acrylate and methyl acrylate ( The molar ratio of butyl acrylate and methyl acrylate is 2: 1) 1/5 of the total mass of the mixed monomer and 1/4 of the mass of the ammonium persulfate aqueous solution with a mole fraction of 0.15%, the temperature is raised to 81 ° C, and the reaction starts after 30 minutes. Add the remaining monomer and initiator aqueous solution dropwise. After the dropwise addition, raise the temperature to 87° C., stir for 2 hours and then lower the temperature to adjust the pH to neutral to obtain the nano-SiO ₂ /acrylic resin composite coating agent.

Example 4: The three-necked flask was heated to 42°C in a water bath, and the emulsifier (the molar ratio of alkylphenol polyoxyethylene ether to sodium dodecylbenzenesulfonate was 2:1) and deionized Water, after the emulsification is uniform, add 0.8% mole fraction of organosilane coupling agent and 0.25% mole fraction of tetraethyl orthosilicate, after stirring at constant temperature for 10 minutes, add 15% mole fraction of butyl methacrylate and acrylic acid Methyl ester (the molar ratio of butyl methacrylate and methyl acrylate is 2: 1) 1/5 of the total mass of the mixed monomer and 1/4 of the quality of the ammonium persulfate aqueous solution with a mole fraction of 0.2%, the temperature is raised to 83 ° C, After reacting for 30 minutes, add the remaining monomer and initiator aqueous solution dropwise. After the dropwise addition, raise the temperature to 90°C, stir for 2 hours, and then lower the temperature to adjust the pH to neutral to obtain the nano-SiO ₂ /acrylic resin composite coating agent.

Example 5: The three-necked flask was heated to 44° C. in a water bath, and an emulsifier (the molar ratio of alkylphenol polyoxyethylene ether to sodium lauryl sulfate was 2:1) and deionized water with a molar fraction of 0.6% was added, After the emulsification is uniform, add 0.85% mole fraction of organosilane coupling agent and 0.15% mole fraction of ethyl orthosilicate, and stir at constant temperature for 10 minutes, then add 15% mole fraction of butyl methacrylate and methyl methacrylate Esters (the molar ratio of butyl methacrylate and methyl methacrylate is 2: 1) 1/5 of the total mass of the mixed monomer and 1/4 of the quality of the ammonium persulfate aqueous solution with a mole fraction of 0.14%, the temperature is raised to 80°C, After reacting for 30 minutes, add the remaining monomer and initiator aqueous solution dropwise. After the dropwise addition, raise the temperature to 90°C, stir for 2 hours, and then lower the temperature to adjust the pH to neutral to obtain the nano-SiO ₂ /acrylic resin composite coating agent.

Example 6: Heat the three-necked flask in a water bath to 40°C, add an emulsifier with a molar fraction of 0.5% (the molar ratio of alkyl polyglycosides to sodium lauryl sulfate is 2:1) and deionized water, and wait for the emulsification to be uniform Finally, adding mole fraction is 0.6% organosilane coupling agent and mole fraction 0.1% orthosilicate ethyl ester, after stirring at constant temperature for 10min, adding mole fraction is 15% butyl acrylate and methyl methacrylate (butyl acrylate The molar ratio of ester and methyl methacrylate is 2: 1) 1/5 of the total mass of the mixed monomer and 1/4 of the mass of the ammonium persulfate aqueous solution with a mole fraction of 0.1%. Add the remaining monomer and initiator aqueous solution dropwise. After the dropwise addition, raise the temperature to 90° C., stir for 2 hours, then lower the temperature and adjust the pH to neutral to obtain a nano-SiO ₂ /acrylic resin composite coating agent.

The nano- _SiO2 /acrylic resin composite finishing agent prepared according to the preparation method of the present invention has excellent properties. After being used for leather finishing, the air permeability and water vapor permeability of the leather are greatly improved, the softness and plumpness of the leather are good, and the aging resistance of the coating is increased. .

Claims (6)

1, letex polymerization original position generates nanometer SiO ₂The preparation method of/acrylate resin composite paint is characterized in that:

The molar fraction compositing range of its raw material is:

Acrylic ester monomer 14-15%

Emulsifying agent 0.40-0.75%

Organo silane coupling agent 0.40-1.1%

Tetraethoxy 0.07-0.3%

Initiator 0.07-0.23%

All the other are deionized water;

Its preparation method is:

With there-necked flask heating in water bath to 40～45 ℃, add emulsifying agent and deionized water, treat emulsification evenly after, add organo silane coupling agent and tetraethoxy, behind the isothermal reaction 10min, 1/4 of 1/5 and initiator solution quality of adding acrylic ester monomer total mass is warmed up to 80～83 ℃, behind the reaction 30min, begin to drip residual acrylic acid esters monomer and initiator respectively, after dropwising, be warming up to 85～90 ℃, cooling is regulated pH to neutral after stirring 2h, promptly gets nanometer SiO ₂/ acrylate resin composite paint;

Described emulsifying agent is 2: 1 formations by nonionogenic tenside and anion surfactant in molar ratio; Nonionogenic tenside is any in alkylphenol polyoxyethylene, alkyl polyglycoside, the sorbitan monooleate (Span80); Anion surfactant is any in sodium lauryl sulphate, the Sodium dodecylbenzene sulfonate;

Described initiator is any in Potassium Persulphate, the ammonium persulphate.

2, letex polymerization original position according to claim 1 generates nanometer SiO ₂The preparation method of/acrylate resin composite paint is characterized in that: described acrylic ester monomer is two or more in butyl acrylate, ethyl propenoate, methyl acrylate, methyl methacrylate, butyl methacrylate, the vinyl-acetic ester.

3, preparation method according to claim 1 and 2 is characterized in that:

With there-necked flask heating in water bath to 40 ℃, the emulsifying agent and the deionized water that add molar fraction 0.5%, emulsifying agent is 2: 1 formations by alkylphenol polyoxyethylene and sodium lauryl sulphate in molar ratio, after treating emulsification evenly, add the organo silane coupling agent of molar fraction 0.4% and the tetraethoxy of molar fraction 0.07%, after constant temperature stirs 10min, the adding molar fraction is 14% butyl acrylate and methyl methacrylate, the mol ratio of butyl acrylate and methyl methacrylate is 2: 1,1/4 of the persulfate aqueous solution quality of 1/5 and the molar fraction 0.07% of mix monomer total mass, system is warmed up to 80 ℃, begin to drip respectively residual monomer and initiator solution behind the reaction 30min, dropping is warming up to 88 ℃ after finishing, cooling is regulated pH to neutral after stirring 2h, promptly gets nanometer SiO ₂/ acrylate resin composite paint.

4, preparation method according to claim 1 and 2 is characterized in that:

With there-necked flask heating in water bath to 45 ℃, the adding molar fraction is 0.5% emulsifying agent and deionized water, emulsifying agent is 2: 1 formations by alkyl polyglycoside and sodium lauryl sulphate in molar ratio, after treating emulsification evenly, add molar fraction and be 0.8% the organo silane coupling agent and the tetraethoxy of molar fraction 0.1%, after constant temperature stirs 10min, the adding molar fraction is 14.5% ethyl propenoate and methyl acrylate, the mol ratio of ethyl propenoate and methyl acrylate is 2: 1,1/4 of the ammonium persulfate aqueous solution quality of 1/5 and the molar fraction 0.1% of mix monomer total mass, be warmed up to 82 ℃, begin to drip respectively residual monomer and initiator solution behind the reaction 30min, dropping is warming up to 86 ℃ after finishing, cooling is regulated pH to neutral after stirring 2h, promptly gets nanometer SiO ₂/ acrylate resin composite paint.

5, preparation method according to claim 1 and 2 is characterized in that:

With there-necked flask heating in water bath to 44 ℃, the adding molar fraction is 0.6% emulsifying agent and deionized water, emulsifying agent is 2: 1 formations by alkylphenol polyoxyethylene and sodium lauryl sulphate in molar ratio, after treating emulsification evenly, add molar fraction and be 0.85% the organo silane coupling agent and the tetraethoxy of molar fraction 0.15%, after constant temperature stirs 10min, the adding molar fraction is 15% butyl methacrylate and polymethacrylic acid methyl ester, the mol ratio of butyl methacrylate and polymethacrylic acid methyl ester is 2: 1,1/4 of the ammonium persulfate aqueous solution quality of 1/5 and the molar fraction 0.14% of mix monomer total mass, be warmed up to 80 ℃, begin to drip respectively residual monomer and initiator solution behind the reaction 30min, dropping is warming up to 90 ℃ after finishing, cooling is regulated pH to neutral after stirring 2h, promptly gets nanometer SiO ₂/ acrylate resin composite paint.

6, preparation method according to claim 1 and 2 is characterized in that:

With there-necked flask heating in water bath to 40 ℃, the adding molar fraction is 0.5% emulsifying agent and deionized water, emulsifying agent is 2: 1 formations by alkyl polyglycoside and sodium lauryl sulphate in molar ratio, after treating emulsification evenly, add molar fraction and be 0.6% the organo silane coupling agent and the tetraethoxy of molar fraction 0.1%, after constant temperature stirs 10min, the adding molar fraction is 15% butyl acrylate and methyl methacrylate, the mol ratio of butyl acrylate and methyl methacrylate is 2: 1,1/4 of the ammonium persulfate aqueous solution quality of 1/5 and the molar fraction 0.1% of mix monomer total mass, be warmed up to 83 ℃, begin to drip respectively residual monomer and initiator solution behind the reaction 30min, dropping is warming up to 90 ℃ after finishing, cooling is regulated pH to neutral after stirring 2h, promptly gets nanometer SiO ₂/ acrylate resin composite paint.