CN112280335B

CN112280335B - PO (polyolefin) membrane coating liquid and preparation method thereof

Info

Publication number: CN112280335B
Application number: CN202011150861.XA
Authority: CN
Inventors: 骆增圳; 顾晓东; 骆增来
Original assignee: Hangzhou Lin'an Lvyuan Additives Co ltd
Current assignee: Hangzhou Lin'an Lvyuan Additives Co ltd
Priority date: 2020-10-24
Filing date: 2020-10-24
Publication date: 2022-03-15
Anticipated expiration: 2040-10-24
Also published as: CN112280335A

Abstract

The application relates to the technical field of coatings, and particularly discloses a PO (polyolefin) membrane coating liquid and a preparation method thereof, wherein the PO membrane coating liquid comprises the following components in percentage by weight: 10-50% of nano aluminum sol; 5-15% of a surfactant; 1-10% of film-forming agent; the balance of pure water; the grain diameter of the nano aluminum sol is 30-100 nm; the surfactant is at least two of polyvinylpyrrolidone, hydroxypropyl methylcellulose, Ninol 6501, polyoxyethylene ether, emulsifier OP series, and allyl alcohol polyoxyethylene polyoxypropylene ether. The PO film coating liquid has the effect of improving the dripping function and the durability of the dripping function of the PO film.

Description

PO (polyolefin) membrane coating liquid and preparation method thereof

Technical Field

The application relates to the technical field of coatings, in particular to PO (polyolefin) membrane coating liquid and a preparation method thereof.

Background

China is a big agricultural country, and the application of the greenhouse film cannot be avoided in agricultural production. The greenhouse film can reduce the humidity of the field, reduce the occurrence degree of plant diseases and insect pests and improve the yield and the quality of crops. However, the fog and drip eliminating performance of the greenhouse film is poor, particularly in winter, water generated by respiration of crops gathers in the greenhouse film to form water drops, external incident light is reflected or refracted, the light transmittance of the greenhouse film is reduced, photosynthesis of the crops is affected, meanwhile, the water drops drop on leaves of the crops to form water films on the leaves, conditions are created for infection and development of germs, and vegetable diseases are caused.

In order to improve the fog dispersal and dripping performance of the greenhouse film, water formed by gathering water fog on the greenhouse film flows downwards along the greenhouse wall to form dripping functional films, and the dripping functional films are generally divided into an inner addition type and an outer coating type. The drip continuity of the internal addition type greenhouse film is poor; the coating type greenhouse film is widely applied, and the coating type greenhouse film is generally a PO film. The PO film is a greenhouse film produced by adopting a raw material of high-grade olefin and other auxiliary agents and adopting an external spraying and drying process. The PO film coating liquid is prepared with alumina sol and silica sol as main material and through adding partial surfactant to modify the surface of PO film to reach relatively low surface tension and thus to raise the dripping performance of PO film.

Aiming at the related technologies, the PO film has good fog-dissipating dripping effect at the initial stage of use, but after a period of time, the PO film has serious water drop hanging condition, and the phenomena of film whitening and coating shedding sometimes occur, thus seriously affecting the subsequent production and use of farmers. The main reasons for the above problems are poor adhesion and low surface tension of the PO film coating solution.

Content of application

In order to improve the dripping function and the durability of the dripping function of the PO film, the application provides a PO film coating liquid and a preparation method thereof.

In a first aspect, the present application provides a PO membrane coating solution, which adopts the following technical scheme:

a PO membrane coating liquid comprises the following components in percentage by weight:

10-50% of nano aluminum sol;

5-15% of a surfactant;

1-10% of film-forming agent;

the balance of pure water;

the particle size of the nano aluminum sol is 30-100 nm;

the surfactant is at least two of polyvinylpyrrolidone, hydroxypropyl methylcellulose, Ninol 6501, polyoxyethylene ether, emulsifier OP series, and allyl alcohol polyoxyethylene polyoxypropylene ether.

By adopting the scheme, the PO film coating solution is formed by matching the nano-alumina sol, the surfactant and the film forming agent. The surfactant is at least two of polyvinylpyrrolidone, hydroxypropyl methylcellulose, Ninol 6501, polyoxyethylene ether, an emulsifier OP series and allyl alcohol polyoxyethylene polyoxypropylene ether, and the two or more surfactants are dissolved in pure water and a film forming agent and improve the dispersion performance and the hydrophilic performance of the PO film coating liquid together with the nano aluminum sol, so that water attached to the PO film spreads on the surface of the PO film and flows downwards along the wall of a greenhouse, and the damage to crops caused by the formation of water beads is reduced. The particle size of the nano aluminum sol is controlled to be 30-100nm, so that the nano aluminum sol has a large specific surface area, the haze of the PO film is reduced, and the nano aluminum sol is better compatible with the film forming agent, so that the film forming effect of the PO film coating solution is improved. The nanometer aluminum sol and the surfactant are matched together, so that the dispersibility of the film forming agent is improved, and the dripping effect of the PO film is uniformly distributed; meanwhile, after the water of the nano aluminum sol is evaporated, the surface of the membrane layer of the PO membrane is regularly and compactly arranged through the cooperation of the nano aluminum sol particles, and more light passes through the PO membrane. In conclusion, the dripping function and the durability of the dripping function of the PO film are improved by adding the film forming agent and the nano aluminum sol and mutually matching with various surfactants.

Preferably, the surfactant is composed of polyvinylpyrrolidone and hydroxypropyl methylcellulose, and the weight ratio of the polyvinylpyrrolidone to the hydroxypropyl methylcellulose is 1 (1-3).

By adopting the scheme, the polyvinylpyrrolidone and the hydroxypropyl methylcellulose are matched with each other, so that the surface tension of the PO membrane coating liquid is smaller, and meanwhile, the surface tension is further reduced by optimizing the proportioning range of the formula.

Preferably, the film forming agent is at least two of polyacrylate resin, polyurethane resin and polyvinyl alcohol resin.

By adopting the scheme, the film formed by the polyacrylate resin, the polyurethane resin and the polyvinyl alcohol resin as the film forming agent has better bonding capability and film forming effect, and has better matching effect with the nano aluminum sol and the surfactant, so that the dripping effect of the PO film is improved, water on the PO film is spread on the surface of the PO film and drips downwards along the wall of the greenhouse, and the damage to crops caused by the formation of water drops is reduced.

Preferably, the film forming agent consists of polyacrylate resin and polyvinyl alcohol resin, and the weight ratio of the polyacrylate resin to the polyvinyl alcohol resin is 1 (3-5).

By adopting the scheme, the polyacrylate resin and the polyvinyl alcohol resin in the film forming agent are matched with each other to form the PO film with strong adhesive force and good film forming effect; in the film forming agent, polyacrylate resin and polyvinyl alcohol resin in the weight ratio of 1 (3-5) are matched with each other, so that the hydrophilic property of polyurethane resin is improved, and the dripping function of the PO film is improved.

Preferably, the polyoxyethylene ether in the surfactant is at least one of siloxane polyoxyethylene ether, fatty alcohol polyoxyethylene ether and heterogeneous fatty alcohol polyoxyethylene ether.

By adopting the scheme, the polyoxyethylene ether is used as a nonionic surfactant and plays a role in dispersing and wetting the PO membrane coating liquid; siloxane polyoxyethylene ether, fatty alcohol polyoxyethylene ether and heterogeneous fatty alcohol polyoxyethylene ether in polyoxyethylene ether are adopted, so that the water solubility and the stability of the PO film coating liquid are improved; meanwhile, the compatibility effect with other surfactants is good, so that the dripping effect of the PO membrane is improved.

Preferably, the emulsifier OP series is emulsifier OP-10.

By adopting the scheme, the emulsifier OP-10 and other surfactants are mutually cooperated, so that the surface tension can be obviously reduced, the dispersing effect is good, the hydrophilic property of the PO film coating liquid is further improved by being matched with the film forming agent, and the surface tension is reduced, so that water on the PO film is spread on the surface of the PO film and flows downwards along the shed wall.

In a second aspect, the present application provides a method for preparing a PO membrane coating solution, which adopts the following technical scheme:

a preparation method of PO membrane coating liquid comprises the following steps:

s1, uniformly mixing the surfactants to obtain a mixed surfactant;

s2, mixing the film forming agent with the balance of water, and diluting to obtain a diluted film forming agent;

s3, adding the nano-alumina sol into the mixed surfactant, and uniformly mixing to obtain a first mixture;

and S4, adding the diluted film forming agent into the first mixture, and mixing to obtain the PO film coating liquid.

Through adopting above-mentioned scheme, technology is comparatively simple, makes simultaneously that film-forming agent, nanometer aluminium sol and surfactant active better dissolve mutually, improves the cooperation effect between the three, obtains stable even PO membrane coating liquid, and then improves the dripping effect of PO membrane coating liquid.

Preferably, the temperature is controlled to be 25-35 ℃ in the step S1.

By adopting the scheme, the temperature is controlled, so that the matching effect between the surfactants is improved while the surfactants are uniformly mixed, and the surfactants are fully matched with the film forming agent to exert the dispersion effect on the coating liquid.

Preferably, the percentage of the diluted film forming agent added in step S4 is 1-10% per hour.

By adopting the scheme, the viscosity of the resin system is adjusted by diluting the film forming agent and dissolving the resin system of the film forming agent, so that the dispersibility and the flowability of the PO film coating liquid are improved.

Preferably, in the step S4, the first mixture is mixed with the diluted film forming agent and then stirred, and the stirring time is controlled to be 24-36 min.

By adopting the above scheme, after the diluted film forming agent, the nanometer alumina sol and the surfactant are mixed, the mixture is stirred to further improve the mixing uniformity of the film forming agent, the nanometer alumina sol and the surfactant, so that the matching effect is improved, the stable and uniform PO film coating liquid is obtained, and the stable dripping effect is obtained.

In summary, the present application has the following beneficial effects:

1. because this application adopts nanometer aluminium sol, surfactant active, film-forming agent and the aqueous phase of surplus to mutually support for water on the PO membrane that scribbles the coating liquid spreads and flows down along the canopy wall on PO membrane surface, reduces the formation of drop of water, thereby causes the injury to crops. The grain size of the nano aluminum sol is 30-100nm, which is beneficial to improving the adhesive force of the PO film coating liquid and reducing the surface tension; meanwhile, a plurality of surfactants are adopted to cooperate with each other, so that the adhesive force of the film forming agent is improved, the water resistance and the surface flexibility of the coating liquid of the PO film are increased, and the surface tension is reduced.

2. In the application, polyacrylate resin and polyvinyl alcohol resin are preferably used as film forming agents, and the weight ratio of the polyacrylate resin to the polyvinyl alcohol resin is limited, so that the film forming property of the film forming agents is stronger, the adhesive property is higher, and the wear resistance and the smoothness of the surface of the PO film are maintained while the adhesive force of the PO film coating liquid is improved by matching with the nano aluminum sol and the surfactant; preferably, polyvinylpyrrolidone and hydroxypropylmethylcellulose are used as raw materials of the surfactant, and the mixing ratio range of the polyvinylpyrrolidone and the hydroxypropylmethylcellulose is limited, so that the surface tension of the PO membrane is reduced. The polyoxyethylene ether in the surfactant preferably adopts siloxane polyoxyethylene ether, fatty alcohol polyoxyethylene ether and isomeric fatty alcohol polyoxyethylene ether, the emulsifier preferably adopts emulsifier OP-10, the Ninol preferably adopts Ninol 6501, and the surfactant is better matched with surfactants such as polyvinylpyrrolidone, hydroxypropyl methyl cellulose and the like, so that the water solubility and the stability of the PO film coating liquid are further improved.

3. The preparation method is simple in preparation process, enables the film-forming agent, the various surfactants and the nano aluminum sol to be better dissolved, and obtains the stable and uniform PO film coating solution. And simultaneously, optimizing the step, namely controlling the speed of adding the diluted film forming agent and the stirring time after the diluted film forming agent is added, so that the film forming agent is uniformly distributed in the PO film coating solution.

Detailed Description

The present application is described in further detail below.

Example 1 a PO film coating solution containing the specific components and weights shown in table 1 was prepared as follows:

s1, mixing the raw materials of the surfactant (polyvinylpyrrolidone and Ninol 6501) uniformly to obtain the mixed surfactant, and controlling the temperature to be 25 ℃ in the mixing process;

s2, mixing the film forming agent with the balance of pure water, and diluting to obtain a diluted film forming agent;

s3, adding nano aluminum sol with the particle size of 30nm into the mixed surfactant, mixing, controlling the stirring speed to be 300r/min, and stirring for 30min to obtain a first mixture;

and S4, adding the diluted film forming agent into the first mixture, wherein the adding speed of the diluted film forming agent is 1kg/h, controlling the stirring speed to be 300r/min after the addition is finished, and stirring for 24min to obtain the PO film coating liquid.

Example 2 a PO film coating solution, which is different from example 1 in the components and weight, was contained in the following table 1.

Examples 3 to 5 a PO film coating solution, which is different from example 2 in the components and weight of the surfactant, was contained as shown in table 1.

TABLE 1 ingredients and weights thereof for examples 1-5

Examples 6 to 9 a PO film coating solution, which is different from example 5 in the composition and weight of the film forming agent, was comprised as shown in table 2.

Example 10 a PO film coating solution, which is different from example 1 in that the film forming agent is polyvinyl chloride resin.

Examples 11 to 13A PO film coating liquid, which is different from example 2 in the components and weight of the polyoxyethylene ether, was prepared in the following manner, and the components and weight thereof are shown in Table 2.

TABLE 2 Components and weights thereof of examples 6-9 and examples 11-13

Example 14 a PO film coating solution, which is different from example 1 in that the nano aluminum sol has a particle size of 100 nm.

Example 15A PO membrane coating solution was prepared which differs from example 2 in that the emulsifier OP-10 was replaced by the same amount of emulsifier OP-4.

Example 16 a PO film coating liquid, which is different from example 1 in that the temperature in step S1 is 35 ℃.

Example 17A PO film coating solution was prepared in the same manner as in example 1 except that the diluted film forming agent was added at a rate of 10kg/h in step S4.

Example 18 a PO film coating solution, which is different from example 1 in that the diluted film forming agent is added at one time in step S4.

Example 19 a PO film coating solution, which is different from example 1 in that the diluted film forming agent was added to the first mixture in step S4, and the mixture was stirred for 36 min.

Comparative example 1 a coating solution was distinguished from example 10 in that an equal amount of non-nanoscale aluminum sol was used instead of nano-aluminum sol.

Comparative example 2 a coating solution was distinguished from example 10 in that the nano aluminum sol had a particle size of 20 nm.

Comparative example 3 a coating solution was distinguished from example 10 in that the nano aluminum sol had a particle size of 120 nm.

Comparative example 4 a coating liquid was distinguished from example 10 in that the surfactant was replaced with an equal amount of pure water.

Comparative example 5 a coating solution was distinguished from example 10 in that the polyoxyethylene ether was replaced with an equal amount of water.

Comparative example 6 a coating solution, the composition and preparation method were as follows:

the components: the mass fraction of the alumina sol is 45 percent, the mass fraction of the silica sol is 45 percent, and the mass fraction of the hydroxymethyl cellulose is 10 percent.

The preparation method comprises the following steps: and adding aluminum sol and silica sol into hydroxymethyl cellulose, and uniformly mixing to obtain the PO membrane coating solution.

Characterization experiment:

static contact angle measurement experiment of PO film coating liquid

Experimental samples: 25 pieces of PO base films not coated with the coating liquid were formed into a rectangle of 4cm × 8cm, examples 1 to 19 and comparative examples 1 to 6 were uniformly coated on the PO base films, respectively, so that the thickness of the formed PO films was 0.1mm, and the PO films after coating stabilization were respectively designated as experimental samples 1 to 19 and comparative samples 1 to 6, and the modified graft PE film and the pure PE film were respectively used as a control sample 1 and a control sample 2.

An experimental instrument: SDC-200S contact angle measuring instrument (SINDIN, Chengdong precision instruments, Inc., Dongguan city) and digital display constant temperature water bath kettle (BHS-1, Baoli scientific research instruments, Inc., Jiangyin city).

The experimental method comprises the following steps: the experimental sample 1 is soaked into 100mL of water at 60 ℃, the water is changed once every hour, samples are taken once, and the contact angle values of the experimental sample 1 at 0h, 4h, 8h, 24h, 10d, 30d, 60d, 90d and 120d are measured and recorded by a PG-X type dynamic and static surface contact angle instrument.

Contact angle measurements were performed on test samples 2-19, comparative samples 1-6, and control samples 1-2, respectively, as described above.

The experimental results are as follows: the results of the static contact angle measurements for the experimental samples 1-19, the comparative samples 1-6, and the control samples 1-2 are shown in Table 3.

TABLE 3 results of static contact Angle measurements of examples 1-19, comparative examples 1-6, and control samples 1-2

In table 3, the static contact angles of the experimental samples 1 to 19, the comparative samples 1 to 6, and the comparative samples 1 to 2 gradually increased with the passage of time, the static contact angles changed rapidly around 20 to 4 hours, and the static contact angles at the later stage changed less and gradually became stable. The static contact angles of examples 1-19 were lower at 120d, with static contact angles ranging from 43.9 to 47.1 °; generally, through a static contact angle test of about 8h, the dripping effect and the quality condition of the PO film can be seen, and the dripping effect of the PO film with the static contact angle of 50 degrees is better. The experimental samples 1-14 have lower surface tension and better hydrophilic stability. The initial static contact angles of the comparative samples 1-6 are larger, and the static contact angles at 0-4h are 53.1-67.3 degrees; the static contact angles of the modified grafted PE film and the pure PE film in the comparison samples 1-2 are both close to 100 degrees and are relatively large and basically do not change along with time.

Comparative experiment samples 1-5 prove that different surfactant components result in different static contact angles; when the surfactant adopts polyvinylpyrrolidone and hydroxypropyl methylcellulose, the polyvinylpyrrolidone and the hydroxypropyl methylcellulose are matched with each other, so that the effect of reducing the surface tension is better. The lactam in the polyvinylpyrrolidone structure is a strong polar group, has a hydrophilic effect, has remarkable binding capacity, has a solubilizing effect, is mutually soluble after being matched with hydroxypropyl methyl cellulose, reduces the surface tension and improves the hydrophilic effect of the coating liquid. When the weight ratio of polyvinylpyrrolidone to hydroxypropylmethylcellulose is limited, the compounding effect is good and the static contact angle in a long-term state is small.

Comparing experimental sample 2, experimental samples 11-13, and comparative sample 5, it can be seen that the polyoxyethylene ether is at least one of siloxane polyoxyethylene ether, fatty alcohol polyoxyethylene ether, and heterogeneous fatty alcohol polyoxyethylene ether, which is helpful for reducing surface tension. Meanwhile, the synergistic effect of the aqueous solution mixed micelle is formed after the components are compounded, the oxyethylene group in the polyoxyethylene ether and water form a hydrogen bond, the hydrophilic effect of the PO membrane is improved, the penetration effect of the fatty alcohol-polyoxyethylene ether is better, the hydrophilic capability of the PO membrane is improved together through the synergistic effect with other surfactants, the surface tension is reduced, the continuity of the hydrophilic performance is prolonged, the dripping performance of the PO membrane is improved, and the problems that the PO membrane hangs water drops and drips to crops are reduced.

Comparing with the experimental samples 5-9, it can be seen that when the film forming agent employs polyacrylate resin and polyvinyl alcohol resin, the formed film has better adhesive ability and film forming effect. The polyvinyl alcohol resin and the polyvinyl alcohol resin are used as hydrophilic resin, so that the adhesion of the surfactant and the film forming agent is better and the PO film is not easy to peel off by improving the adhesion performance of the PO film. The film forming agent and the surfactant act together to reduce the static contact angle and the surface tension, so that the dripping function of the PO film is improved, water on the surface of the PO film drops along the side wall of the PO film, and the long-acting property of the dripping function of the PO film is prolonged.

Comparing the experimental sample 10 with the comparative samples 1-3, it can be seen that the nano aluminum sol is an inorganic high-molecular multivalent polymer, the nano aluminum sol is matched with polyacrylate resin and polyurethane resin, and has better intermiscibility, and the properties of the resin are not affected after being uniformly mixed; in addition, when the nano aluminum sol with the particle size of 30-100nm is adopted, the specific surface area of the nano aluminum sol is large, and the nano aluminum sol has good dispersibility and permeability when mixed with a surfactant; meanwhile, when water in the nano aluminum sol is evaporated, the nano aluminum sol is firmly adhered to the surface of the PO film by erecting a molecular bridge between the surfactant and the interface of the PO film, so that a hydrophilic layer is formed on the surface of the PO film, and the effect of preventing water drops from hanging on the PO film and dropping to crops is achieved.

Comparing the experimental sample 2 and the experimental sample 15, it can be seen that the static contact angle of the emulsifier OP-10 is small, and the emulsifier OP-10 and other surfactants cooperate with each other to reduce the surface tension of the PO film, improve the hydrophilic effect, and prevent the occurrence of water-hanging drops on the PO film, thereby affecting the growth of crops. Comparing the experimental sample 10 with the experimental samples 17-19, it can be known that the hydrophilicity of the PO film coating solution can be improved by controlling the addition speed of the diluted film forming agent so that the diluted film forming agent is sufficiently contacted with the nano aluminum sol and the surfactant and is matched with the nano aluminum sol and the surfactant; the diluted film forming agent is stirred after being heated in the step S4, so that the diluted film forming agent, the surfactant and the nano alumina sol are uniformly mixed, the matching effect is better, the static contact angle is reduced, the surface tension is reduced, and the dripping effect and the continuity of the dripping effect of the PO film are improved.

The embodiments of the present invention are preferred embodiments of the present application, and the scope of protection of the present application is not limited by the embodiments, so: all equivalent changes made according to the structure, shape and principle of the present application shall be covered by the protection scope of the present application.

Claims

1. The PO membrane coating liquid is characterized by comprising the following components in percentage by weight:

10-50% of nano aluminum sol;

5-15% of a surfactant;

1-10% of film-forming agent;

the balance of pure water;

the particle size of the nano aluminum sol is 30-100 nm;

the raw materials of the surfactant comprise at least two of polyvinylpyrrolidone, hydroxypropyl methylcellulose, Ninol 6501, polyoxyethylene ether, emulsifier OP series and allyl alcohol polyoxyethylene polyoxypropylene ether;

the film forming agent consists of polyacrylate resin and polyvinyl alcohol resin, and the weight ratio of the polyacrylate to the polyvinyl alcohol resin is 1 (3-5);

the polyoxyethylene ether in the surfactant comprises at least one of siloxane polyoxyethylene ether, fatty alcohol polyoxyethylene ether and isomeric fatty alcohol polyoxyethylene ether;

s1, uniformly mixing the raw materials of the surfactant at the temperature of 25-35 ℃ to obtain a mixed surfactant;

s4, adding the diluted film forming agent into the first mixture, wherein the percentage of the diluted film forming agent added per hour is 1-10%; and mixing the first mixture and the diluted film forming agent, and stirring for 24-36min to obtain the PO film coating liquid.

2. The PO membrane coating solution of claim 1, wherein the surfactant comprises polyvinylpyrrolidone and hydroxypropyl methylcellulose, and the weight ratio of the polyvinylpyrrolidone to the hydroxypropyl methylcellulose is 1 (1-3).

3. A PO film coating solution according to claim 1 characterized in that said emulsifier OP series is emulsifier OP-10.