KR101250884B1 - Coating composite for moisture-absorption - Google Patents

Abstract

The present invention discloses a coating for water absorption.
The water-absorbing coating agent according to the present invention converts the water-absorbing coating precursor consisting of a nonionic hydrophilic single molecule and an ionic hydrophilic single molecule having an acid as a functional group, and converts the water-absorbing coating precursor into a liquid three-dimensional network structure resin. It characterized in that it comprises a curing agent and a polyurethane-based binder for securing flexibility and adhesion when coating, whereby, a liquid type moisture absorption coating agent that can improve the problem of the water absorption powder having low adhesion, flexibility is low It can be manufactured by low temperature process including room temperature with wide range of application due to liquid phase characteristics.

Description

Coating for moisture absorption {Coating composite for moisture-absorption}

The present invention relates to a water-absorbing coating, and more particularly, to provide a liquid-type water-absorbing coating that can improve the problem of water-absorbing powder having low adhesion and flexibility and has a wide range of application due to liquid phase characteristics. It relates to a water-absorbing coating that can be produced by a low temperature process, including room temperature.

Damage caused by the penetration of moisture directly beneath the exposed surfaces of products such as air conditioning filters, concrete crack preventing sealants and wire cables is a well known problem. Such damage includes corrosion by water as well as oxidative damage caused by the reaction of water on the surface of the product.

In addition, in the seawater environment, in particular the problems associated with flooding appear in combination with the salty environment. The presence of salts in such an aqueous environment promotes decomposition by oxidation.

Far cable among the wire cable is often used in a long time underground or submerged for a long time. Protection from water injury as described above is important for the structural integrity of the cable and the successful performance of the functions the cable is intended to perform, for example, surrounding the conductors inside the cable with fibers such as yarn for water absorption, The surface of the yarn is coated with a moisture-absorbing powder to absorb the water that penetrates when the cable is damaged.

The water absorption powder is prepared by adding a crosslinking agent to an acrylic acid-based monomer, polymerizing it, and then drying and pulverizing it.

In addition, the water-absorbing powder is also applied to newborn baby diapers to absorb the aqueous solution such as urine of babies in a short time to keep the surface of the diaper pad dry.

However, such powder powder has a problem in that a separate process or an additional cost is generated because it is not attached to the fibers of the yarn or diaper used in the cable and is attached using a separate adhesive or thinner.

In addition, the water absorption powder is used in various fields related to the characteristics of absorbing or controlling the aqueous solution, for example, by mixing the above powder in a sand desert where water cannot be stored, providing a soil that maintains moisture for a long time, It is used in a wide variety of applications such as pads that absorb liquid from fruits, water reducing agents that increase the strength of hardened cement by reducing the amount of water used in cement, and floor pads that can effectively remove liquids spilled on the floor. It is the same as having the problem of low adhesion or lack of flexibility.

Therefore, the technical problem to be solved by the present invention is to provide a moisture absorption coating agent to prevent the reduction of the adhesion or flexibility of the water absorption powder and to ensure the thermal stability of the substrate to be applied.

The present invention to solve the first technical problem described above,

A water-absorbing coating precursor consisting of a nonionic hydrophilic monomolecule and an ionic hydrophilic monomolecule having an acid as a functional group, a curing agent for converting the water-absorbing coating precursor into a liquid three-dimensional network structure resin, and flexibility and adhesion in coating. It provides a moisture-absorbing coating comprising a polyurethane-based binder for securing.

According to one embodiment of the invention, the nonionic hydrophilic monomolecule is acrylamide, methacrylamide, maleic acid, maleic anhydride, hydroxyethyl acrylate ( Hydroxyethyl acrylate, Hydroxypropyl acrylate, Hydroxyethyl methacrylate, Hydroxypropyl methacrylate, Glycidyl methacrylate, Dimethylamino Ethyl acrylamide (dimethylaminoethyl acrylamide), dimethylaminopropyl acrylamide (dimethylaminopropyl acrylamide) may be at least one selected from the group consisting of acryllamidopropyl trimehthyl ammonium chloride.

According to another embodiment of the present invention, the ionic hydrophilic single molecule is acrylic acid (methacrylic acid) and 2-acrylamito-2-methylpropanesulfonic acid (2-acrylamido-2-methylpropane sulfonic acid) may be at least one selected from the group consisting of.

According to another embodiment of the present invention, the ionic hydrophilic single molecule may be in the form of a salt (salt), the neutralization degree of the salt may be 40 to 85%.

According to another embodiment of the present invention, the curing agent is N-methylol acrylamide, N-methylol methacrylamide, N, N-dimethylaminoethyl acrylate (N, N-dimethylaminoethyl acrylate), N, N-dimethylaminopropyl acrylamide (N, N-dimethylaminopropyl acrylamide) and polyethylene glycol monoacrylate (polyethyleneglycol monoacrylate) may be at least one selected from the group consisting of.

According to another embodiment of the present invention, the curing agent may be at least one selected from the group consisting of melamine resin (melamine), epoxy resin (Epoxy) and polyaziridine (polyaziridine).

According to another embodiment of the present invention, the water-absorbing coating agent is polyvinyl alcohol, polyvinyl pyrolidone, starch, starch derivatives, cellulose At least one selected from the group consisting of cellulose derivatives, polyacrylic acid, and polyglycol may be further included.

According to another embodiment of the present invention, the polyurethane-based binder is water dispersible and may be a nonionic or anionic dispersion resin.

According to another embodiment of the present invention, the polyurethane binder may have a number average molecular weight of 10,000 to 1,000,000, an average particle size of 0.01 to 0.1 micrometer (μm), and an elongation of 500 to 1,500%.

The present invention provides a liquid-type water absorption coating agent that can improve the problem of the water-absorbing powder having low adhesion, flexibility, and has a wide range of application due to the characteristics of the liquid phase and can be manufactured by low temperature processes including room temperature. .

Hereinafter, the present invention will be described in detail.

The water-absorbing coating agent according to the present invention converts the water-absorbing coating precursor consisting of a nonionic hydrophilic single molecule and an ionic hydrophilic single molecule having an acid as a functional group, and converts the water-absorbing coating precursor into a liquid three-dimensional network structure resin. It is characterized by including a curing agent and a polyurethane-based binder for ensuring flexibility and adhesion during coating.

The above-described water-absorbing coating agent is a polymer formed by polymerizing a hydrophilic monomer in an aqueous solution, and refers to a super absorbent polymer composition which can absorb water in water or in the air through moisture drying and curing.

The nonionic hydrophilic monomolecule is acrylamide, methacrylamide, maleic acid, maleic anhydride, hydroxyethyl acrylate, hydroxypropyl acrylate. (Hydroxypropyl acrylate), hydroxyethyl methacrylate (Hydroxyethyl methacrylate), hydroxypropyl methacrylate (Hydroxypropyl methacrylate), glycidyl methacrylate (glycidyl methacrylate), dimethylaminoethyl acrylamide, di Methylaminopropyl acrylamide or acryllamidopropyl trimehthyl ammonium chloride is used to secure water absorption.

In addition, acrylic acid, methacrylic acid, or 2-acrylamido-2-methylpropane sulfonic acid may be used as the ionic hydrophilic single molecule. there is,

They can be used directly or in the form of sodium, potassium, ammonium and salts, with a degree of neutralization of 40 to 85% being preferred.

If the degree of neutralization is less than 40%, the adhesion to the substrate to be coated is increased, but there may be a problem that the absorption is lowered. On the contrary, if the degree of neutralization is greater than 85%, the above-mentioned acid groups having reactivity are insufficient. In this case, a desired degree of curing or delay in curing can be brought about during the curing reaction.

In addition, the curing agent N-methylol acrylamide, N-methylol methacrylamide, N, N-dimethylaminoethyl acrylate (N, N-dimethylaminoethyl acrylate) N, N-dimethylaminopropyl acrylamide or polyethyleneglycol monoacrylate may be used, which forms linear polymers in a three-dimensional network. It can optionally be used for applications where the curing temperature is above 100 ° C.

On the other hand, melamine resin (epamine), epoxy resin (polyoxyridine) or polyaziridine (polyaziridine) can be used when the curing temperature requires a low temperature, for example, the process in which the coating material, such as fibers, thermal deformation is concerned, 40 Can be used above ℃.

In addition, polyvinyl alcohol, polyvinyl pyrolidone, starch, starch derivative (starch) in order to change the flexibility, improve adhesion or adjust the absorption rate in the water-absorbing coating of the present invention derivatives, cellulose, cellulose derivatives, polyacrylic acid, or polyglycol may be used, and the use thereof may be 2 to 10 weight parts based on 100 parts by weight of the water-absorbing coating agent. The addition is preferred, if less than 2 parts by weight, there may be no effect on flexibility and adhesion, and on the contrary, exceeding 10 parts by weight may adversely affect the absorbency or the curability.

Meanwhile, the polyurethane-based binder is water dispersible and may be a nonionic or anionic disperse resin.

Here, the nonionic polyurethane dispersing resin may be prepared by urethane reaction with acetone solvent at 60 to 80 ° C., dispersing with acetone solvent at 1000 to 3000rpm high speed stirring, and extracting acetone solvent, wherein the solid content is 30%. In addition, the anionic polyurethane dispersion resin is a polyol and an isocyanate, a hydrophilic ionomer (DMPA (Di-methylol propionic acid) or DMBA (Di-methylol butanoic acid) in the urethane 80 ~ 100 ℃ atmosphere The reaction can be prepared by preparing a prepolymer, neutralizing it with an amine, and then dispersing it. The polyurethane binder has a number average molecular weight of 10,000 to 1,000,000 and an average particle size of 0.01 to 0.1 micro (μm). , The elongation is preferably between 500 and 1,500%.

≪ Example 1 >

An aqueous sodium hydroxide solution was added to the reactor under an atmosphere of nitrogen gas reflux, and the temperature of the reactor was maintained at 40 degrees. Next, 30 g of acrylic acid monomer and 60 g of hydroxypropyl acrylate monomer were added to the reactor over 30 minutes, followed by stirring at 60 rpm. Next, stirring was continued, and 3 g of polyaziridine and 40 g of nonionic polyurethane dispersing resin (SUM-1000, SUM-1000) were added as a curing agent, and the reaction temperature was maintained at 90 degrees. Next, to cool to 60 degrees to prepare a coating for absorbing moisture according to the invention.

<Example 2>

A water-absorbing coating agent was prepared in the same manner as in Example 1 except that 40 g of anionic polyurethane dispersion resin (manufactured by hydroxyl polymer, SUM-2090) was used.

<Example 3>

A water-absorbing coating agent was prepared in the same manner as in Example 1, except that 10 g of polyvinyl alcohol was added to the non-ionic polyurethane dispersion resin.

<Example 4>

A water-absorbing coating agent was prepared in the same manner as in Example 2, except that 10 g of polyvinyl alcohol was further added to the anionic polyurethane dispersion resin.

<Experimental Example 1>

To measure the absorption rate,

Aramid yarn (yarn) was prepared by measuring the weight of 10 pieces 1m in length (W1), the average value was described, the aramid yarn (yarn) 0.7 mm after immersion in the water absorption coating agent according to Examples 1 to 4. The nozzle was passed through a hot air drying / curing at 60 ° C. for 20 minutes, and the average weight was measured (W2).

On the other hand, in order to measure the average value as described above, the aramid yarn coated in ultrapure water was immersed for 1 minute and then extracted and left in the air for 10 minutes to remove moisture other than the absorbed moisture and weighed (W3), which was not coated in ultrapure water The aramid yarn was immersed for 1 minute and then extracted and left for 10 minutes in the air to remove moisture other than the absorbed water. Then, the weight was measured (W4), and the coating amount and the water absorption rate are shown in Table 1 based on the following equation.

Coating amount (%) = (W2-W1) / W2 X 100

% Absorption = (W3-W4) / (W2-W1)

division Example 1 Example 2  Example 3  Example 4 Coating amount 5 5 5 5 Absorption rate 84 88 78 76

Referring to Table 1, it can be seen that the water-absorbing coating agent according to Examples 1 to 4 can be cured at a low temperature that does not change the physical properties of the aramid yarn, the water absorption is also very good.

<Experimental Example 2>

To measure the desorption rate,

After preparing several aramid yarn (yarn) to a length of 10m, the aramid yarn (yarn) is immersed in the water-absorbing coating agent according to Examples 1 to 4, respectively, and then passed through a 0.7 mm nozzle 60 ℃, hot air drying / curing for 20 minutes The weight was measured to describe the average value (W1). After the temperature of the coated yarn reaches room temperature, it is wound on a test tube having an outer diameter of 3 cm and then unwound again. The same process is repeated three times, then weighed and averaged (W2). Desorption rate was calculated based on the following equation, it is shown in Table 2 below.

Desorption rate (%) = (W1-W2) / W1 X 100

division Example 1 Example 2  Example 3  Example 4 Desorption Rate 4% less than 3% less than 2% less than 2% less than

Referring to Table 2, it can be seen that the moisture-absorbing coating agent according to Examples 1 to 4 has almost no detachment, and thus has excellent adhesion.

<Experimental Example 3>

To measure flexibility,

After preparing several aramid yarn (yarn) to a length of 10m, the aramid yarn (yarn) is immersed in the water-absorbing coating agent according to Examples 1 to 4, respectively, and then passed through a 0.7 mm nozzle 60 ℃, hot air drying / curing for 20 minutes I was. After the temperature of the coated yarn reached room temperature, after selecting a specific part and folding it 10 times, the marks on the folded part were compared with the yarn before coating. If the folds between the two samples are nearly similar, they are excellent (marked up to 5), and if the coated yarns produce relatively clear marks, the criteria for judging them as bad (at least 0) are established. Those in the middle are marked as good by the difference in degree, and are shown in Table 3 below.

division Example 1 Example 2  Example 3  Example 4 flexibility 4 5 3 3

Referring to Table 3, the water-absorbing coating agent according to Examples 1 to 4, despite the excellent adhesion of Table 2, it can be confirmed that the flexibility is very excellent.

Claims (9)

delete Acrylamide, methacrylamide, maleic aicd, maleic anhydride, hydroxyethyl acrylate, hydroxypropyl acrylate, hydroxyethyl Hydroxyethyl methacrylate, hydroxypropyl methacrylate, glycidyl methacrylate, dimethylaminoethyl acrylamide, dimethylaminopropyl acrylamide ) And acryllamidopropyl trimehthyl ammonium chloride, and at least one nonionic hydrophilic single molecule selected from the group consisting of:
It is composed of acrylic acid, methacrylic acid and 2-acrylamido-2-methylpropane sulfonic acid, which are ionic hydrophilic molecules with acid as functional groups. Moisture-absorbing coating precursor consisting of at least one selected from the group;
N-methylol acrylamide, N-methylol methacrylamide, N, N-di, which is a curing agent for converting the water-absorbing coating precursor into a liquid three-dimensional network structure resin At least one selected from the group consisting of N, N-dimethylaminoethyl acrylate, N, N-dimethylaminopropyl acrylamide, and polyethyleneglycol monoacrylate ; And
Polyurethane-based binder for ensuring flexibility and adhesion when coating; Water-absorbing coating comprising a.
Acrylamide, methacrylamide, maleic aicd, maleic anhydride, hydroxyethyl acrylate, hydroxypropyl acrylate, hydroxyethyl Hydroxyethyl methacrylate, hydroxypropyl methacrylate, glycidyl methacrylate, dimethylaminoethyl acrylamide, dimethylaminopropyl acrylamide ) And acryllamidopropyl trimehthyl ammonium chloride, and at least one nonionic hydrophilic single molecule selected from the group consisting of:
It is composed of acrylic acid, methacrylic acid and 2-acrylamido-2-methylpropane sulfonic acid, which are ionic hydrophilic molecules with acid as functional groups. Moisture-absorbing coating precursor consisting of at least one selected from the group;
At least one selected from the group consisting of melamine resin (melamine), epoxy resin and polyaziridine, which are curing agents for converting the water-absorbing coating precursor into a liquid three-dimensional network structure resin; And
Polyurethane-based binder for ensuring flexibility and adhesion when coating; Water-absorbing coating comprising a.
The method according to claim 2 or 3,
The ionic hydrophilic monomolecule may be in the form of a salt, the salt having a neutralization degree of 40 to 85% of the water absorption coating.
delete delete The method according to claim 2 or 3,
The water-absorbing coating agent is polyvinyl alcohol, polyvinyl pyrolidone, starch, starch derivatives, cellulose, cellulose derivatives, polyacrylic acid (polyacrylic acid) and polyglycol (polyglycol) at least one selected from the group consisting of water-absorbing coating, characterized in that it further comprises.
The method according to claim 2 or 3,
The polyurethane-based binder is water dispersible, water-absorbing coating, characterized in that the non-ionic or anionic disperse resin.
The method of claim 8,
The polyurethane-based binder has a number average molecular weight of 10,000 to 1,000,000, an average size of 0.01 to 0.1 ㎛, elongation is 500 to 1,500% coating material for moisture absorption.