KR0161741B1 - Process for preparing acrylate type gel - Google Patents

Abstract

In the present invention, a butyl acrylate is added to ethylhexyl acrylate, and azobisisobutyronitrile and carbon tetrachloride are added to prepare a copolymerized precursor, and a peroxide is added to the copolymerized precursor thus prepared, at a temperature of 60 to 80 ° C. It is an invention for a method for producing a polymer gel and a polymer gel prepared by the step of self-crosslinking by maintaining for 4 hours.

Description

Method for preparing acrylate gel using peroxide as crosslinking agent

The present invention relates to a method for producing an acrylate gel using a peroxide as a crosslinking material and an acrylate gel produced thereby. More specifically, the present invention can be easily produced at low production cost by using a peroxide as a crosslinking agent to form a crosslink and swell the macromolecules which do not participate in the crosslinking reaction by swelling the macromolecules formed by the crosslinking reaction. In addition, the present invention relates to a method for producing an acrylate-based polymer gel having excellent properties such as electrical insulation.

In general, when moisture penetrates electronic communication equipment from the external environment, corrosion and the like decrease greatly in the size of the equipment. In particular, many connections in electronic communication equipment are sensitive to corrosion caused by moisture. When this condition occurs, telephone communication, loss of transmission data, and interruption of supply of the operating current may cause operation of the electronic communication equipment to be impossible. Often happens.

In order for corrosion to occur in the atmosphere, water must be present to act as an electrolyte through which current can flow. Therefore, in order to prevent the corrosion of electronic communication equipment by the external environment, the area to be protected must be completely blocked from moisture.

Representative methods to date have been used to prevent water soaking to prevent corrosion include gaskets, hot melt adhesives and grease. Gasket, which is usually made of rubber, deteriorates and loses elasticity after a long time, and in this state, water penetrates easily into the equipment, causing catastrophic damage, which does not guarantee long-term reliability.

On the other hand, hot melt adhesive is excellent in long-term reliability and moisture resistance, but there is a disadvantage in that the use of a firearm during construction is greatly reduced in the field operability.

In addition, in the case of grease, the construction is easy, while the viscosity in the fine drops fall easily and has a disadvantage of hardening in long-term use. Therefore, in this case, there is a problem in that the grease's ability to prevent water penetration is lost.

In order to improve this conventional problem, the gel material is used as a moisture proofing process material recently.

Gel is a swelling by adding a solvent to a macromolecule having a chemically cross-linked three-dimensional network structure, almost no change in its characteristics even at high or low temperatures, and automatically recovers after shape deformation caused by external force. Have. In addition, the installation does not require a firearm or tools, and has the advantage that can be reused.

Accordingly, the present inventors have studied to prepare a polymer gel composition for moisture-proof insulation having excellent water repellency by maximizing these advantages of the gel polymer formed by the crosslinking reaction. The reaction and the acrylate-based polymer gel composition for moisture-proof insulation of the present invention swelled by low molecular weight polymer precursors that do not participate in the crosslinking reaction.

First, the present inventors consider the following to develop the polymer gel of the present invention.

First, in order for the gel to be removed from the insulating surface and reusable, the cohesive force must be large compared to the adhesive force, and thus the molecular weight of the gel must be as large as possible. However, increasing the molecular weight increases the viscosity rapidly and the fluidity decreases, making handling difficult. Accordingly, the method of preparing the polymer gel composition of the present invention preferentially makes a compound having a viscosity in the range that can be handled, and then injected into a required container or the like and then reacts again in the container, thereby improving the molecular weight. It was.

Second, in order for the gel to be commercially available, the gel must be soft and highly flexible and have high surface adhesion as well as self-cohesion. In addition, it is advantageous to use a monomer having low manufacturing cost and low glass transition temperature. In addition, the prepared polymer gel should have a chemical structure that does not dissolve or react with containers made of general-purpose thermoplastic resins such as polyethylene, polypropylene, and vinyl chloride resin.

In general, acrylic monomers do not react with plastic containers and form a transparent polymer compound which is inexpensive and has a low glass transition temperature. However, it has a disadvantage in that the molecular weight is rapidly increased by the auto-acceleration reaction in the polymerization process and the odor peculiar to the monomer, and thus it is difficult to solve this problem.

Therefore, in the case of the acrylic monomer, a solvent is used to control the auto acceleration reaction and its own viscosity. However, when a solvent remains in the polymerization precursor, it is necessary to completely remove the solvent since bubbles are formed in the polymer gel when the remaining solvent volatilizes. Therefore, it is preferable to use a small amount of the solvent as possible, it is easy to remove the boiling point of the solvent is easy to remove the large chain transfer constant (chain transfer constant) should be able to suppress the rapid increase in molecular weight.

In the present invention, in consideration of the above contents, a polymer gel for moisture-proof insulation having a desired property was prepared using a general-purpose acrylate monomer having a glass transition temperature significantly lower than room temperature.

Hereinafter, the manufacturing method of the acryl-type polymer gel composition for moisture proof insulation which used the peroxide of this invention as a crosslinking agent is demonstrated in detail.

In the manufacturing process of the present invention, azobisisobutyronitrile and carbon tetrachloride are added to an acrylate monomer in which ethylhexyl acrylate and butyl acrylate are mixed to produce a copolymer precursor which is a base material of a gel.

Here butyl acrylate provides harder properties than the gel produced by ethylhexyl acrylate alone synthetic precursors, the amount used being about 10 to 25% by weight based on the total weight of the reactants (ethylexyl acrylate-butyl acrylate). It is preferable to add.

The azobisisobutyronitrile used to prepare the polymer precursor to prepare the polymer gel composition of the present invention serves as an initiator to cause a polymerization reaction between monomers of the mixed base material, and it is about 0.5 to about the total reactant weight. 3% is used, preferably about 1.9% by weight.

In the present invention, carbon tetrachloride is used as a chain transfer agent. In other words, when the molecular weight of the polymer precursor is increased, the viscosity increases and the fluidity decreases, making handling in the gelation reaction quite difficult. In particular, since the acrylic monomer tends to increase molecular weight rapidly during the polymerization reaction, a chain transfer agent having a large chain transfer constant must be added to obtain a polymerization precursor having an ideal viscosity. Considering these conditions, the present invention is to use carbon tetrachloride as a chain transfer agent. In the present invention, since the amount of carbon tetrachloride used as the chain transfer agent is removed during the preparation of the gel of the present invention, it is irrelevant to the gel composition, but it is preferable to use about 10 to 45 wt% of the total reactants (ethylhexyl acrylate-butyacrylate). desirable.

As a solvent for mixing the precursor of the present invention, an aromatic hydrocarbon solvent, an ester solvent such as ethyl acetate, hexyl acetate or butyl acetate, and a ketone solvent such as methyl ethyl ketone may be used alone or as a mixture thereof. In consideration of the ethyl acetate is particularly preferred.

In the production method of the present invention, when the solvent remains, it has an undesirable effect such as causing corrosion due to the generation of bubbles. On the other hand, when bulk or mass polyreaction is used without using a solvent, the viscosity of the obtained polymer is too high, and only a local reaction may occur during the gelation process. Therefore, it is preferable to use solution polymerization using a solvent in the manufacturing method of the polymer gel composition of this invention. However, when the solvent is used in excess, problems due to the remaining solvent as described above may occur, so that the reaction should be removed after the reaction is completed, and the reaction rate is slowed. In addition, since the acrylic monomer has a rapid reaction rate and causes an autoacceleration reaction in which the reaction is completed within a few minutes after the start of the reaction, it is not preferable to use a too small amount of solvent to prevent such an autoacceleration reaction. In view of these points, the preferred amount of solvent in the present invention is preferably 30 to 70%, and most preferably 50% of the total weight of the reactants in each reaction.

After the peroxide is added to the copolymer precursor prepared as a crosslinking agent, the crosslinking reaction is maintained at 60 to 80 ° C. for 2 to 4 hours. The crosslinking agent used at this time is preferably 1 to 5% by weight of the reactant weight. The peroxide crosslinking agent used in the present invention thermally decomposes upon heating to form radicals, and these radicals attack the highly active α hydrogen in the main chain of ethyllexyl acrylate, thereby forming a crosslinking site in the chain. The formation of these interchain bonds results in the formation of large crosslinked polymer gels of reticulated structure.

As the peroxide that can be used as the crosslinking agent in the present invention, various peroxides that can be used to generate crosslinks in the field of organic chemistry may be used, but benzoyl peroxide is particularly preferable. The reason is that when the benzoyl peroxide is used as the crosslinking agent, the crosslinking reaction takes a long time, but there is an advantage that a relatively stable gel can be obtained. In particular, when benzoyl peroxide is used as the crosslinking agent, it is preferable to dissolve and add the crosslinking agent for complete mixing with the polymer precursor.

The carbon tetrachloride and the solvent used in the preparation of the polymer gel of the present invention are all volatilized at the temperature at which the crosslinking reaction occurs, so that they do not affect the gelation process and do not cause corrosion of the metal product due to bubble generation.

In the preparation of the polymer gel composition of the present invention, when the amount of the peroxide that is the crosslinking agent is small, no crosslinking reaction occurs or the crosslinking time is long, and when 5% or more is added, the crosslinking occurs excessively and inhibits the swelling action, thus preventing the formation of the gel. do. In addition, if the temperature is low or not maintained for sufficient time, the crosslinking reaction does not occur sufficiently and the viscosity is considerably decreased. If the temperature is higher than 80 ° C, the crosslinking reaction rate is increased to shorten the gel formation time, whereas the gel has a large amount of Bubbles will contain. In particular, when there is a bubble in the presence of carbon tetrachloride is not completely removed from the polymer precursor in the presence of a problem that the metal is easily corroded.

In addition, if the gel is maintained for a long time in the process of preparing the gel, the crosslinking reaction occurs excessively, and the viscosity is greatly increased, and thus it cannot be utilized as a gel.

In order to produce a complete gel, it is preferable to add a swelling agent in order to impart soft properties after crosslinking. However, in the composition of the present invention, the chains which do not participate in the crosslinking reaction without the addition of a swelling agent are subjected to self-expansion which enters and expands between the crosslinking networks. Accordingly, it can be seen that when the crosslinking time is too long, crosslinking occurs excessively, and the swelling effect is hardly exhibited, thereby forming an undesirable gel having excessive viscosity.

In the preparation of the polymer gel of the present invention, a small amount of additives, for example, plasticizers and the like, which are commonly used in the technical field of the present invention, may be added to control physical properties during the crosslinking reaction.

The polymer gel prepared by the manufacturing method of the present invention has the following properties (Examples 2 and 3), when the insulation of the product coated with the polymer gel composition prepared by the manufacturing method of the present invention when drying and immersion In addition to being able to pass the international standard (bell standard) in all, it was confirmed that the product ensures excellent moisture-proof insulation and durability that is stable even under corrosive conditions.

In addition, the polymer gel composition prepared by the manufacturing method of the present invention is a very economical and industrial desiccant that can be used very simply and inexpensively by applying to various electronic devices placed in the external environment without any complicated equipment.

The following examples illustrate the invention in more detail, and do not limit the scope of the invention.

Example 1

Table 1 below shows the four polymer gel composition components of this example. Each component is expressed in% by weight of the total composition.

Ethylhexyl acrylate and butyl acrylate (hereinafter referred to as reactants in amounts of 50% by weight of these reactants, mixed in an amount such that it has the composition of Table 1 above) and 1.9% by weight of azobisiso Butyronitrile is dissolved in carbon tetrachloride in the amounts shown in Table 1 above and added to prepare a copolymerized precursor.

To the polymer precursor prepared as described above, 4% by weight of benzoyl peroxide of the reactant was added to ethyl acetate, dissolved and mixed, and maintained at 60 to 80 ° C. for 2 to 4 hours, thereby self-crosslinking and self-swelling. This occurs to prepare the polymer gel of the present invention.

Example 2

Since the use of the gel mainly serves to protect the connection area of the electronic and communication equipment, the insulation resistance characteristics are basically important. Therefore, in this example, the insulation resistance of the compositions 1 to 4 prepared in Example 1 was tested by the following test method.

For the eight terminals in the terminal box, a 0.4mm core wire was connected to the station terminal, and a 1.0mm outdoor telephone line was connected to the subscriber terminal, and a cap filled with gel was applied to each terminal for use as a sample.

After applying a DC 500V voltage to each terminal for 1 minute, the insulation resistance between each terminal and ground, and a terminal and a terminal was measured (Hewlett Packard 4337A high resistance meter). After the insulation resistance measurement sample was immersed in 1m deep water for 48 hours, a voltage of DC 500V was applied for 1 minute and then insulation resistance was measured.

The results are shown in Table 2 below.

At internationally recognized Bell standards, insulation properties are at least 10 Since it is specified that the ohm (ohm) or more, from the above results, the polymer gel composition of the present invention passes through these regulations, and passed all the bell specifications even after maintaining in water for two days.

Therefore, it can be seen that the polymer gel composition according to the present invention has excellent insulation properties. In addition, the polymer gel composition of the present invention was transparent enough to distinguish the incoming core wire even at a thickness of 20mm.

Example 3

Corrosion experiments were performed on the polymer gel compositions 1 to 5 of Example 1. After covering a polymer gel having a diameter of 10 cm on a 15 × 15 cm brass plate, the brass plate was immersed in 4% brine for 24 hours and then left in hydrochloric acid vapor for a week.

As a result, no corrosion occurred at the portion to which the polymer gel was applied, but the uncoated portion was corroded to cyan.

From these results, it can be seen that the polymer gel composition prepared according to the present invention protects the metal surface with little effect on the corrosive environment.

Claims (7)

(a) adding butyl acrylate to ethylhexyl acrylate and adding azobisisobutyronitrile and carbon tetrachloride to prepare a copolymerized precursor. (b) Method of preparing a polymer gel, characterized in that the step of cross-linking by adding a peroxide to the copolymerized precursor prepared in (a) and maintained for 2 to 4 hours at a temperature of 60 to 80 ° C. The process of claim 1 wherein the butyl acrylate is about 10 to 25 weight percent of the weight of the reactant (ethylhexylacrylate-butylacrylate). The process of claim 1 wherein the azobisisobutyronitrile is about 0.5 to 3.0 weight percent of the reactant weight. 4. A process according to claim 3, wherein the azobisisobutyronitrile is 1.9% by weight of the reactant weight. 2. The process of claim 1 wherein the carbon tetrachloride uses from about 10 to 45 weight percent of the reactant species. 2. A process according to claim 1 wherein the peroxide is benzoyl peroxide. (a) adding butyl acrylate to ethylhexyl acrylate and adding azobisisobutyronitrile and carbon tetrachloride to prepare a copolymerized precursor. (b) A polymer gel prepared by the method of claim 2, wherein the polymer is prepared by the step of self-crosslinking by adding a peroxide to the copolymerized precursor prepared in (a) and maintaining it at a temperature of 60 to 80 ° C for 2 to 4 hours.